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  • 1.
    Angserud, Jenny
    et al.
    Sandvik Mining.
    From, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Wallin, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    On a wear test for rock drill inserts2013In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 301, no 1-2, p. 109-115Article in journal (Refereed)
    Abstract [en]

    In this work wear of cemented carbide rock drill inserts is evaluated by using a rotating rock cylinder as counter surface. The influence on wear rate and degradation mechanisms from varying dry and wet conditions, cemented carbide grade, abrasive particle type and size as well as load is studied. The used abrasive media are alumina and silica.

    Test results show high repeatability and the three tested cemented carbide grades can be differentiated, even though their relative difference in sample hardness is modest. The loads used, 100–200 N, are sufficiently high to cause fracture and wear of the granite rock. The degraded microstructure of inserts tested under wet and dry conditions as well as with added silica particles is similar to field worn inserts. Hence, the same wear mechanisms occur and the test successfully mimics rock drill wear. Typical insert wear includes cracking and fragmentation of WC grains, depletion of Co binder phase and adhered material originating from the rock.

    Tests under dry conditions always cause less measured wear than tests under wet conditions.

    Addition of alumina particles, which are harder than the used cemented carbide samples, causes a significant wear rate increase but does not provide wear similar to rock drilling.

  • 2.
    Angserud, Jenny
    et al.
    Sandvik Mining.
    From, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Wallin, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    On a wear test for rock drill inserts2013Conference paper (Refereed)
    Abstract [en]

    In this work wear of cemented carbide rock drill inserts is evaluated by using a rotating rock cylinder as counter surface. The influence on wear rate and degradation mechanisms from varying dry and wet conditions, cemented carbide grade, abrasive particle type and size as well as load is studied. The used abrasive media are alumina and silica.

    Test results show high repeatability and the three tested cemented carbide grades can be differentiated, even though their relative difference in sample hardness is modest. The loads used, 100–200 N, are sufficiently high to cause fracture and wear of the granite rock. The degraded microstructure of inserts tested under wet and dry conditions as well as with added silica particles is similar to field worn inserts. Hence, the same wear mechanisms occur and the test successfully mimics rock drill wear. Typical insert wear includes cracking and fragmentation of WC grains, depletion of Co binder phase and adhered material originating from the rock.

    Tests under dry conditions always cause less measured wear than tests under wet conditions.

    Addition of alumina particles, which are harder than the used cemented carbide samples, causes a significant wear rate increase but does not provide wear similar to rock drilling.

  • 3. Arhammar, C.
    et al.
    Silvearv, F.
    Bergman, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Pedersen, H.
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    A theoretical study of possible point defects incorporated into alpha-alumina deposited by chemical vapor deposition2013In: Theoretical Chemistry accounts, ISSN 1432-881X, E-ISSN 1432-2234, Vol. 133, no 2, p. 1433-Article in journal (Refereed)
    Abstract [en]

    The energetics and electronic structure of carbon, chlorine, hydrogen, and sulfur in alpha-Al2O3 was investigated by first principles and thermodynamical calculations. These species are present in the gas phase during the synthesis of alpha-Al2O3 by chemical vapor deposition (CVD) but little is known of their solubility in this compound. The heat of formation from standard reference states of the elements varying the chemical potential of each element was calculated. An attempt to model the actual conditions in the CVD process was made, using the species and solid compounds present in a common CVD process as reference states. Our calculations suggest that sulfur from the catalyzing agent H2S will not solve in alpha-Al2O3 during deposition by CVD. It is found that the neutral chlorine and hydrogen interstitial defects display the lowest heat of formation, 281 and 280 kJ/mol, respectively, at the modeled CVD conditions. This energy is too high in order for neutral defects to form during CVD of alpha-Al2O3 at any significant amounts. The charged defects and their compensation were studied. Carbon substituting oxygen is found to be energetically favored under the modeled CVD conditions, considering carbon dioxide as competing species to solid solubility in alpha-Al2O3 at an energy of -128 kJ/mol. However, care needs to be taken when choosing the possible competing carbon-containing phases. Compensation of carbon substituting for oxygen by oxygen vacancies takes place at 110 kJ/mol from standard reference states, graphite, fcc-Al and O-2. The carbon solubility in Al2O3 is difficult to measure with standard analysis techniques such as X-ray diffraction and energy dispersive X-ray spectroscopy, but several stable compounds in the Al-C-O are available in the literature.

  • 4. Borgh, Ida
    et al.
    Hedstrom, Peter
    Persson, Tomas
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Borgenstam, Annika
    Agren, John
    Odqvist, Joakim
    Microstructure, grain size distribution and grain shape in WC-Co alloys sintered at different carbon activities2014In: International Journal of Refractory Metals and Hard Materials, ISSN 0263-4368, Vol. 43, p. 205-211Article in journal (Refereed)
    Abstract [en]

    The properties of cemented carbides strongly depend on the WC grain size and it is thus crucial to control coarsening of WC during processing. The aim of this work was to study the effect of sintering at different carbon activities on the final microstructure, as well as the coarsening behavior of the WC grains, including the size distribution and the shape of WC grains. These aspects were investigated for five WC-Co alloys sintered at 1410 degrees C for 1 h at different carbon activities in the liquid, in the range from the graphite equilibrium (carbon activity of 1) to the eta (M6C) phase equilibrium (carbon activity of 0.33). The grain size distribution was experimentally evaluated for the different alloys using EBSD (electron backscatter diffraction). In addition, the shape of the WC grains was evaluated for the different alloys. It was found that the average WC grain size increased and the grain size distribution became slightly wider with increasing carbon activity. Comparing the two three-phase (WC-Co-eta and WC-Co-graphite) alloys a shape change of the WC grains was observed with larger grains having more planar surfaces and more triangular shape for the WC-Co-graphite alloy. It was indicated that in alloys with a relatively low volume fraction of the binder phase the WC grain shape is significantly affected by impingements. Moreover, after 1 h of sintering the WC grains are at a non-equilibrium state with regards to grain morphology. (C) 2013 Elsevier Ltd. All rights reserved.

  • 5.
    Fowler, Lee
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Janson, Oscar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Antibacterial investigation of titanium-copper alloys using luminescent Staphylococcus epidermidis in a direct contact test2019In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 97, p. 707-714Article in journal (Refereed)
    Abstract [en]

    Commercially pure titanium (CP-Ti), used as oral implants, is often populated by various bacterial colonies in the oral cavity. These bacteria can cause Peri-implantitis, leading to loss of bone tissue and failure of implants. With the increased awareness of antibiotic resistance, research has been directed towards alternative solutions and recent findings have indicated titanium-copper (Ti-Cu) alloys as a promising antibacterial material. The aim of this study was to produce homogeneous Ti-Cu alloys, with various concentrations of copper, and to characterise their antibacterial properties through direct contact tests, using luminescent bacteria, in addition to traditional materials characterisation techniques. Samples of CP-Ti and four different Ti-Cu alloys (1, 2.5, 3 and 10 wt%Cu) were produced in an arc-furnace, heated treated and rapidly quenched. X-ray diffraction revealed that Ti2Cu, was present only in the 10 wt%Cu alloy, however, scanning electron microscopy (SEM) indicated precipitates at the grain boundaries of the 3 wt%Cu alloy, which were confirmed to be of a copper rich phase by energy dispersive x-ray spectroscopy (EDS) analysis. EDS line scans confirmed that the alloys were homogenous. After 6 h, a trend between copper content and antibacterial rate could be observed, with the 10 wt%Cu alloy having the highest rate. SEM confirmed fewer bacteria on the 3 wt%Cu and especially the 10 wt%Cu samples. Although the 10 wt%Cu alloy gave the best antibacterial results, it is desired that the Cu concentration is below similar to 3 wt%Cu to maintain similar mechanical and corrosive performance as CP-Ti. Therefore, it is proposed that future work focuses on the 3 wt%Cu alloy.

  • 6.
    Fowler, Lee
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Masia, Nomsombuluko
    Advanced Materials Division, Mintek, Randburg 2124, South Africa; School of Chemical and Metallurgical Engineering, and DST-NRF Centre of Excellence in Strong Materials, hosted by the University of the Witswatersrand, Johannesburg 2000, South Africa.
    Cornish, Lesley A.
    School of Chemical and Metallurgical Engineering, and DST-NRF Centre of Excellence in Strong Materials, hosted by the University of the Witswatersrand, Johannesburg 2000, South Africa.
    Chown, Lesley H.
    School of Chemical and Metallurgical Engineering, and DST-NRF Centre of Excellence in Strong Materials, hosted by the University of the Witswatersrand, Johannesburg 2000, South Africa.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman-Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Development of Antibacterial Ti-Cu-x Alloys for Dental Applications: Effects of Ageing for Alloys with Up to 10 wt% Cu2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 23, article id 4017Article in journal (Refereed)
    Abstract [en]

    Peri-implantitis, a disease caused by bacteria, affects dental implants in patients. It is widely treated with antibiotics, however, with growing antibiotic resistance new strategies are required. Titanium-copper alloys are prospective antibacterial biomaterials, with the potential to be a remedy against peri-implantitis and antibiotic resistance. The aim of this study was to investigate Ti-Cux alloys, exploring how Cu content (up to 10 wt%) and ageing affect the material properties. Electron microscopy, X-ray diffraction, hardness testing, bacteriological culture, and electrochemical testing were employed to characterize the materials. It was found that alloys with above 3 wt% Cu had two phases and ageing increased the volume fraction of Ti2Cu. An un-aged alloy of 5 wt% Cu showed what could be Ti3Cu, in addition to the α-Ti phase. The hardness gradually increased with increased Cu additions, while ageing only affected the alloy with 10 wt% Cu (due to changes in microstructure). Ageing resulted in faster passivation of the alloys. After two hours the aged 10 wt% Cu alloy was the only material with an antibacterial effect, while after six hours, bacteria killing occurred in all alloys with above 5 wt% Cu. In conclusion, it was possible to tune the material and antibacterial properties of Ti-Cux alloys by changing the Cu concentration and ageing, which makes further optimization towards an antibacterial material promising.

  • 7.
    Fowler, Lee
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Van Vuuren, Arno Janse
    Centre for High Resolution Transmission Electron Microscopy, Department of Physics, Nelson Mandela University, 6031 Port Elizabeth, South Africa.
    Goosen, William
    Centre for High Resolution Transmission Electron Microscopy, Department of Physics, Nelson Mandela University, 6031 Port Elizabeth, South Africa.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman-Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Investigation of copper alloying in a TNTZ-Cux alloy2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 22, article id 3691Article in journal (Refereed)
    Abstract [en]

    Alloying copper into pure titanium has recently allowed the development of antibacterial alloys. The alloying of biocompatible elements (Nb, Ta and Zr) into pure titanium has also achieved higher strengths for a new alloy of Ti-1.6 wt.% Nb-10 wt.% Ta-1.7 wt.% Zr (TNTZ), where strength was closer to Ti-6Al-4V and higher than grade 4 titanium. In the present study, as a first step towards development of a novel antibacterial material with higher strength, the existing TNTZ was alloyed with copper to investigate the resultant microstructural changes and properties. The initial design and modelling of the alloy system was performed using the calculation of phase diagrams (CALPHAD) methods, to predict the phase transformations in the alloy. Following predictions, the alloys were produced using arc melting with appropriate heat treatments. The alloys were characterized using energy dispersive X-ray spectroscopy in scanning transmission electron microscopy (STEM-EDS) with transmission Kikuchi diffraction (TKD). The manufactured alloys had a three-phased crystal structure that was found in the alloys with 3 wt.% Cu and higher, in line with the modelled alloy predictions. The phases included the α-Ti (HCP-Ti) with some Ta present in the crystal, Ti2Cu, and a bright phase with Ti, Cu and Ta in the crystal. The Ti2Cu crystals tended to precipitate in the grain boundaries of the α-Ti phase and bright phase. The hardness of the alloys increased with increased Cu addition, as did the presence of the Ti2Cu phase. Further studies to optimize the alloy could result in a suitable material for dental implants.

  • 8.
    Haglöf, F.
    et al.
    KTH Royal Inst Technol, Mat Sci & Engn, S-10044 Stockholm, Sweden;Sandvik Coromant R&D, S-12679 Stockholm, Sweden.
    Kaplan, B.
    Sandvik Coromant R&D, S-12679 Stockholm, Sweden.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D, S-12679 Stockholm, Sweden.
    Blomqvist, A.
    Sandvik Coromant R&D, S-12679 Stockholm, Sweden.
    Selleby, M.
    KTH Royal Inst Technol, Mat Sci & Engn, S-10044 Stockholm, Sweden.
    Experimental study of carbides in the Ti-Cr-C system2019In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 54, no 19, p. 12358-12370Article in journal (Refereed)
    Abstract [en]

    The Ti-Cr-C system has been studied by producing samples within the MC-M3C2-M7C3 (M=Ti, Cr) and MC-M3C2-graphite equilibria. The main purpose was to determine the solubility of Cr in MC; however, the solubility of Ti in M3C2 and M7C3 was also of interest, as well as the C content in MC. Heat treatments have been performed at 1673 and 1773 K for 300 h. Thereafter, the phase compositions have been measured with energy-dispersive X-ray spectroscopy (EDS) and wavelength-dispersive X-ray spectroscopy (WDS). X-ray diffraction (XRD), in combination with Rietveld refinement, has been used to determine the lattice parameter for MC. Density functional theory (DFT) calculations were performed to estimate the lattice parameter for MC as a function of composition, and the Rietveld refined lattice parameters for MC have then been recalculated to compositions in order to verify the EDS measurements. The results show that the EDS and XRD measurements give equal results. One conclusion is that, with the current conditions, 300 h is a sufficient heat treatment time in order to reach thermodynamic equilibrium. The other main conclusion is that the solubility of Cr in MC, in general, was overestimated by previous studies due to too short heat treatment times, but also that the solubility is very temperature dependent, especially for the MC-M3C2-graphite equilibrium. This clear temperature dependence was not taken into account in the existing thermodynamic description found in the literature.

  • 9.
    Heinrichs, Jannica
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Olsson, Mikael
    Dalarna University.
    Cemented carbide wear initiation in sliding contact with iron ore2019In: Proceedings of 2nd Sweden-China Symposium on Tribology, 2019Conference paper (Other academic)
  • 10.
    Heinrichs, Jannica
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Olsson, Mikael
    Dalarna University.
    Influence of cemented carbide binder type on wear initiation in rock drilling – investigated in sliding wear against magnetite rock2019In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 85, article id 105035Article in journal (Refereed)
    Abstract [en]

    Cemented carbides, containing hard WC grains in a ductile Co binder, are commonly used as the rock crushing part of rock drills. They generally work well and show moderate and gradual wear in rock drilling applications. However, due to health issues, an alternative to Co is sought for, which will not compromise the performance. In the present work, the initiation of wear of cemented carbides with the two alternative binders Ni and Fe are investigated and compared to the common Co containing material in a sliding test. The sliding counterpart is magnetite, representing a rock type generally causing slow wear of the cemented carbides.

    The results show that magnetite is immediately transferred to the cemented carbide thus forming thin layers, mainly on top of the binder, and WC grain fragments are removed. The chain of events is similar irrespective of binder, however the severity shows a strong dependence. The cemented carbide grade with the Ni binder shows relatively rapid wear initiation, compared to that with the Fe binder that shows moderate initiation and that with Co that is barely worn at all.

  • 11.
    Jones, H. G.
    et al.
    National Physical Laboratory, Teddington, UK.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant, Sandvik Rock Tools.
    Kritikos, M.
    Sandvik Coromant, Sandvik Rock Tools.
    Mingard, K. P.
    National Physical Laboratory, Teddington, UK.
    Gee, M. G.
    National Physical Laboratory, Teddington, UK.
    Examination of wear damage to rock-mining hardmetal drill bits2017In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 66, p. 1-10Article in journal (Refereed)
    Abstract [en]

    WC/Co mining bits from a drill head used for drilling holes for roof support bolts in a mine were examined using a focused ion beam scanning electron microscope (FIB-SEM). This was combined with energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analyses to study the chemical interaction between the drill bit and the rock. It was found that at the surface of the buttons there was depletion of cobalt, change in chemistry of the remaining binder regions, and changes to the morphology of the WC grains. Tribochemistry calculations were done to understand the possible formation of silicides at the surface of the drill bits, and thus emphasise the importance of quartz content in rock on wear. The evidence of mechanical damage combined with chemical reactions is another step towards understanding the complete wear process in hardmetal mining tools.

  • 12.
    Kaplan, B.
    et al.
    Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    Odelros, S.
    Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    Kritikos, M.
    Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    Bejjani, R.
    Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    Study of tool wear and chemical interaction during machining of Ti6Al4V2018In: INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, ISSN 0263-4368, Vol. 72, p. 253-256Article in journal (Refereed)
    Abstract [en]

    The present study concerns an investigation of the wear on three uncoated cemented carbide grades, with differing binder content and grain size, during longitudinal turning of Ti6Al4V as a function of cutting speed. The creater wear at end of tool life is studied in detail using electron microscopy and X-ray diffraction. It is observed that decreasing binder content results in slower wear progression and longer tool life. The microstructure of the adhered layer is also dependent on the binder content, where a lower amount of binder results in an increase of dark precipitates in the adhered layer. X-ray diffraction confirms the presence of bcc-W as a chemical wear product at the interface. Diffraction peaks corresponding to cubic (Ti,V)C are also occasionally observed.

  • 13. Kaplan, Bartek
    et al.
    Blomqvist, Andreas
    Selleby, Malin
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Thermodynamic analysis of the W-Co-Cr system supported by ab initio calculations and verified with quaternary data2015In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 50, p. 59-67Article in journal (Refereed)
    Abstract [en]

    The present work aims at assessing the W-Co-Cr system with focus on including the ternary R-phase in the thermodynamic description. Enthalpies of formation at 0 K of all considered R-phase end-members are calculated using density functional theory and used in the assessment due to the scarceness of the experimental information. The resulting assessment is verified by comparing with recent experimental data in the W-Co-Cr-C quaternary system.

  • 14. Kaplan, Bartek
    et al.
    Markstrom, Andreas
    Blomqvist, Andreas
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Selleby, Malin
    Thermodynamic analysis of the Co-Cr-C system2014In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 46, p. 226-236Article in journal (Refereed)
    Abstract [en]

    A reassessment of the thermodynamic description of the Co-Cr-C system was performed to take into account recent experimental information on the solubility of Co in Cr-based carbides. Density Functional Theory (DFT) calculations coupled with phonon calculations were performed to calculate the heat capacity and Gibbs energies of formation of stable and metastable carbides in the Co-Cr-C system as a function of temperature, within the limits of the Harmonic or the Quasi Harmonic Approximation. Resulting Gibbs energies were compared with earlier experimental studies and assessments, where calculated values for Cr23C6, Cr7C3 and Cr3C2 from the present work were seen to fall within the experimental scatter. The calculated heat capacity and Gibbs energy of formation as a function of temperature for the metastable Co3C2 compound together with recent experimental information was used in the evaluation of the thermodynamic parameters. As a result, the new and improved thermodynamic description accounts for the solubility of Co in M3C2 in contrast to previous descriptions, where this was neglected due to a complete lack of experimental information. Furthermore, a better representation of previously reported liquidus temperatures was achieved, without increasing the number of parameters in the liquid phase. Other relevant features of the phase diagram and thermochemical properties were also well represented.

  • 15. Kaplan, Bartek
    et al.
    Markstrom, Andreas
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Selleby, Malin
    Experimental Determination of the Solubility of Co in the Cr-Based Carbides Cr23C6, Cr7C3, and Cr3C22014In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 45A, no 11, p. 4820-4828Article in journal (Refereed)
    Abstract [en]

    Thermodynamic calculations based on the CALPHAD method are nowadays often applied in the design of new materials due to increasing demands on shorter lead times for development. However, such calculations rely heavily on the assessed thermodynamic descriptions, which in turn rely on the amount and quality of available experimental data, especially for binary and ternary sub-systems. The ternary Co-Cr-C system is an extremely important subsystem to, e.g., multi-component cemented carbide grades, such as W-Co-Cr-M-C (M = Ti,Ta,Nb,V,Zr,Hf), as well as Cr-containing Co-base alloys. In the case of the Co-Cr-C system, there is a lack of reliable data on the solubility of Co in Cr-carbides. Therefore, the present work concerns an experimental study of the solubility of Co in all three of the Cr-based carbides, i.e., Cr23C6, Cr7C3, and Cr3C2. This was done by synthesizing appropriate samples in the M7C3+M23C6+liquid and M7C3+M3C2+graphite three-phase fields. The results show that a recent thermodynamic description of the Co-Cr-C system is unable to reproduce the experimentally determined solubilities. Therefore, the present study provides important input for future alloy development and improvement of the thermodynamic description of the Co-Cr-C system.

  • 16. Kaplan, Bartek
    et al.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Schwind, Martin
    Selleby, Malin
    Thermodynamic calculations and experimental verification in the WC-Co-Cr cemented carbide system2015In: INT J REFRACT MET H, ISSN 0263-4368, Vol. 48, p. 257-262Article in journal (Refereed)
    Abstract [en]

    Tungsten carbide and cobalt have always been, and still are, the foundation of cemented carbides. Modem grades include several other alloying elements, apart from just WC-Co, added for several different purposes. For example, by adding chromium it is possible to produce extremely fine grained grades compared to straight WC-Co grades and thus the freedom to tailor the properties of the material is increased. By applying thermodynamic calculations it is possible to design the material and also avoid some of the costly trial-and-error procedures. However, there is also a need for experimental verification in order to have confidence in the predictive calculations. The present work concerns the application of thermodynamic calculations to some relevant compositions together with experimental verification in the WC-Co-Cr system. Special focus is given to the limiting conditions for precipitation of unwanted phases with regards to the Cr-content in the binder, C-content and melting temperatures. No regard is taken to the presumable Cr-solubility in the WC phase itself. (C) 2014 Elsevier Ltd. All rights reserved.

  • 17. Kaplan, Bartek
    et al.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Schwind, Martin
    Selleby, Malin
    Thermodynamic calculations and experimental verification in the WC-Co-Cr cemented carbide system (Reprint of Int. Journal of Refractory Metals and Hard Materials vol 48, pg 257-262, 2015)2015In: INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, ISSN 0263-4368, Vol. 49, p. 400-405Article in journal (Refereed)
    Abstract [en]

    Tungsten carbide and cobalt have always been, and still are, the foundation of cemented carbides. Modem grades include several other alloying elements, apart from just WC-Co, added for several different purposes. For example, by adding chromium it is possible to produce extremely fine grained grades compared to straight WC-Co grades and thus the freedom to tailor the properties of the material is increased. By applying thermodynamic calculations it is possible to design the material and also avoid some of the costly trial-and-error procedures. However, there is also a need for experimental verification in order to have confidence in the predictive calculations. The present work concerns the application of thermodynamic calculations to some relevant compositions together with experimental verification in the WC-Co-Cr system. Special focus is given to the limiting conditions for precipitation of unwanted phases with regards to the Cr-content in the binder, C-content and melting temperatures. No regard is taken to the presumable Cr-solubility in the WC phase itself.

  • 18.
    Meingast, Arno
    et al.
    Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    Coronel, Ernesto
    Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    Blomqvist, Andreas
    Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    Wahnstrom, Goran
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden.
    Lattemann, Martina
    Sandvik Coromant R&D, S-12680 Stockholm, Sweden.
    High resolution STEM investigation of interface layers in cemented carbides2018In: INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, ISSN 0263-4368, Vol. 72, p. 135-140Article in journal (Refereed)
    Abstract [en]

    Cemented carbides with sub-micron grain size have increased the need to restrict grain growth during sintering. Commonly used inhibitors like V, Ti, and Cr have been observed to form interface layers in the interfaces between WC grains and the Co binder. Atomistic modeling has predicted the composition and thickness of the interface layers. Earlier, the interface layers have been characterized qualitatively using high resolution transmission electron microscopy (TEM). To get more information about the structure and composition of the interface layers in a Ti containing cemented carbide in this work, Z contrast imaging and spectroscopy using scanning transmission electron microscopy (STEM) have been combined. Elemental maps revealing the structure of the interface layers will be presented.

  • 19.
    Norgren, Susanne
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Kusoffsky, Alexandra
    On the solubility of chromium in the cubic carbide and M7C3 carbide in the WC-Co-Cr-Me systems (Me = Ti, Nb, Ta and Zr)2013In: INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, ISSN 0263-4368, Vol. 40, no SI, p. 24-26Article in journal (Refereed)
    Abstract [en]

    The solubility of Cr in cubic carbides in the systems WC-Co-TiC and WC-Co-NbC has been determined using equilibrium samples. Thermodynamic calculations were used to design the alloys through extrapolations of Gibbs energy expressions. The alloys were designed to have a microstructure containing the following phases: WC, liquid, M7C3, graphite and cubic carbide. The alloys were investigated using scanning electron microscopy and analyzed using energy-dispersive X-ray spectrometry. The present work shows how Cr solubility depends on which cubic carbide former is present.

  • 20.
    Odelros, S.
    et al.
    Sandvik Coromant R&D, Sweden.
    Kaplan, B.
    Sandvik Coromant R&D, Sweden.
    Kritikos, M.
    Sandvik Coromant R&D, Sweden.
    Johansson, Malin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D, Sweden.
    Experimental and theoretical study of the microscopic crater wear mechanism in titanium machining2017In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 376, p. 115-124Article in journal (Refereed)
    Abstract [en]

    Continuous turning of Ti6AI4V with uncoated WC-Co cutting tool inserts mainly results in crater wear on the rake face of the tool. The crater is located close to the cutting edge and increases in size with increased time in cut. The flank wear remains minor until the point when the crater reaches a critical size so that the edge deforms plastically and edge breakage occurs. To understand the crater wear degradation mechanisms, this study focuses on examining the worn tool at different stages, using both experimental and theoretical techniques, as well as under static and dynamic conditions. A layer of adhered work-piece material is observed in the crater. The present study shows both experimental and theoretical evidence of carbon depletion of the WC in the crater and formation of W (bcc) at the interface during wet continuous longitudinal turning of Ti6AI4V. This has been demonstrated for the first time. In addition, indications of a carbon rich compound, possibly MC, where M=Ti, V and W, are also observed. These observations are verified by simulation of the diffusion process. Furthermore, diffusion simulations indicate that a liquid may form at the tool/chip interface in the crater zone during machining. Turning is a dynamic process, however, to study the chemical driving forces in this system under static conditions, a means of verification of which phases will form is needed. Therefore, a diffusion couple consisting of the same materials is prepared and analyzed. Similar results are obtained for the diffusion couple as for the worn tool, indicating that the chemical wear is an important degradation parameter. The diffusion couple results are also compared to a numerical simulation of the diffusion process.

  • 21. Stenlund, Patrik
    et al.
    Omar, Omar
    Brohede, Ulrika
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norlindh, Birgitta
    Johansson, Anna
    Lausmaa, Jukka
    Thomsen, Peter
    Palmquist, Anders
    Bone response to a novel Ti–Ta–Nb–Zr alloy2015In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 20, p. 165-175Article in journal (Refereed)
  • 22. Stenlund, Patrik
    et al.
    Omar, Omar
    Brohede, Ulrika
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norlindh, Birgitta
    Johansson, Anna
    Lausmaa, Jukka
    Thomsen, Peter
    Palmquist, Anders
    Bone response to a novel Ti-Ta-Nb-Zr alloy2015In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 20, p. 165-175Article in journal (Refereed)
    Abstract [en]

    Commercially pure titanium (cp-Ti) is regarded as the state-of-the-art material for bone-anchored dental devices, whereas the mechanically stronger alloy (Ti-6Al-4V), made of titanium, aluminum (Al) and vanadium (V), is regarded as the material of choice for high-load applications. There is a call for the development of new alloys, not only to eliminate the potential toxic effect of Al and V but also to meet the challenges imposed on dental and maxillofacial reconstructive devices, for example. The present work evaluates a novel, dual-stage, acid-etched, Ti-Ta-Nb-Zr alloy implant, consisting of elements that create low toxicity, with the potential to promote osseointegration in vivo. The alloy implants (denoted Ti-Ta-Nb-Zr) were evaluated after 7 days and 28 days in a rat tibia model, with reference to commercially pure titanium grade 4 (denoted Ti). Analyses were performed with respect to removal torque, histomorphometry and gene expression. The Ti-Ta-Nb-Zr showed a significant increase in implant stability over time in contrast to the Ti. Further, the histological and gene expression analyses suggested faster healing around the Ti-Ta-Nb-Zr, as judged by the enhanced remodeling, and mineralization, of the early-formed woven bone and the multiple positive correlations between genes denoting inflammation, bone formation and remodeling. Based on the present experiments, it is concluded that the Ti-Ta-Nb-Zr alloy becomes osseointegrated to at least a similar degree to that of pure titanium implants. This alloy is therefore emerging as a novel implant material for clinical evaluation.

  • 23.
    Toller, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D, Stockholm, Sweden..
    Life time of cemented carbide inserts with Ni-Fe binder in steel turning2017In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 376, p. 1822-1829Article in journal (Refereed)
    Abstract [en]

    Health concerns associated with cobalt powder are a strong motivator for conducting research on alternative binders for cemented carbides. It has previously been shown possible to make cemented carbides with alternative binders, which offer good hardness and toughness. However, it is not fully known if these cemented carbides can be successfully used as metal cutting tools. In this study we have tested turning inserts from cemented carbide with a nickel-iron binder and compared these with cobalt based reference inserts in dry face turning of steel in a pairwise comparison. To facilitate relevant comparisons, both the alternative binder and the reference cemented carbide are gradient sintered and coated in the same way as commercial turning grades. It is found that the life time in this dry face turning test is only approximately 15% shorter with the nickel-iron binder than with the cobalt reference, which motivates further studies with this alternative binder. Flaking of the coating and thus less coating adhesion was identified as one reason for the shorter life time.

  • 24.
    Toller, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Larsson, Tommy
    Seco Tools AB R&D.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D.
    CVD Coating Adhesion on Metal Cutting Insertswith Alternative Binders2015Conference paper (Other academic)
  • 25.
    Toller, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Liu, Chunxin
    Holmström, Erik
    Sandvik Coromant R&D.
    Larsson, Tommy
    Seco Tools AB R&D.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D.
    Investigation of Cemented Carbides with Alternative Binders after CVD Coating2015Conference paper (Refereed)
  • 26.
    Toller, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Liu, Chunxin
    Royal Institute of Technologi.
    Holmström, Erik
    Sandvik Coromant R&D.
    Larsson, Tommy
    Seco Tools AB R&D.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D.
    Investigation of Cemented Carbides with Alternative Binders after CVD Coating2017In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 62, p. 225-229Article in journal (Refereed)
    Abstract [en]

    Due to health concerns surrounding the use of cobalt as a binder for tungsten carbide in cemented carbides there is a drive to find an alternative binder. Although there are many publications on cemented carbides with alternative binders very few consider the possibility to coat these materials. In this work four different binder compositions containing iron-nickel or iron-nickel-cobalt and a pure cobalt reference are investigated with respect to coating ability. It is shown that it is possible to coat these cemented carbides with alternative binders through the same chemical vapor deposition process that is commonly used for cobalt based inserts and get similar coating structure. It is further shown that it can be done without the formation of η-phase and with comparable scratch test adhesion.

  • 27.
    Toller, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D.
    Mechanisms of plastic deformation in WC-Co and WC-Ni-Fe turning inserts2017Conference paper (Refereed)
    Abstract [en]

    This work is an inital study on microstructural features along the flank face of plastically deformed turning inserts. The turning inserts used are WC-NiFe hardmetals that have been used in face turning with noticeable plastic deformation and flaking of the coating at the cutting edge limiting the life time. It was found that the flank face could be split into five zones of different conditions during the turning test based on the outer appearance. These five zones also exhibited different signs of plastic deformation in their microstructure, seen in both focused ion beam cross sections and in a mechanically polished cross section, including what is believed to be cavity and lamellae formation from grain boundary sliding. The microscopic plastic deformation of the turning inserts in this work were compared with litterature on deformed WC-Co.

  • 28.
    Toller-Nordström, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Gee, Mark
    National Physical Laboratory.
    Holmberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mingard, Ken
    National Physical Laboratory.
    Lilja, Mirjam
    Sandvik Mining and Rock Technology, R&D Rock Tools division.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Abrasive wear of hardmetals with a binder phase forming deformation induced martensiteManuscript (preprint) (Other academic)
    Abstract [en]

    Hardmetals with alternative binder phases with compositions tailored for specific applications may be used to achieve improved performance of tools. In this paper an iron based binder phase that has previously been found to undergo a phase transformation from austenite to martensite as a response to plastic deformation is tested in three different tests: Micro scratch tests, micro abrasion and rock turning. All three tests show characteristic wear of the tungsten carbide and removal of binder phase from the surface.

  • 29.
    Toller-Nordström, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mingard, K.
    Natl Phys Lab, Hampton Rd, Teddington TW11 0LW, Middx, England.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik Coromant R&D, Lerkrogsvagen 13, S-12680 Stockholm, Sweden.
    Deformation induced martensite in a Fe-Ni-Co binder phase of a hardmetal2019In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 155, article id 109783Article in journal (Refereed)
    Abstract [en]

    This paper investigates deformation induced martensite in a hardmetal binder phase with target composition 50 wt% iron, 25 wt% nickel and 25 wt% cobalt. A fully austenitic ion polished cross-section surface was scratched with a diamond indenter and investigated with X-ray and electron diffraction. It was found that the top 100 nm of the scratched surface contained a mixture of austenite and a second phase identified as BCC/BCT martensite. The martensite grain size varied between a few 10 nm and a over 1 mu m in dimensions.

  • 30.
    Toller-Nordström, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Orientation of binder phase lamellae formed through grain boundary sliding in hardmetal turning insertsManuscript (preprint) (Other academic)
  • 31.
    Toller-Nordström, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Östby, Jonas
    Sandvik Coromant R&D.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Towards understanding plastic deformation in hardmetal turning inserts with different bindersIn: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917Article in journal (Refereed)
    Abstract [en]

    This works investigates the deformation of coated hardmetal turning inserts used until the end of life. Three different hardmetals with binder phases, pure cobalt, 15 wt% iron 85 wt% nickel and 85 wt% iron 15 wt% nickel are tested. It is shown that grain boundary sliding accommodated by formation of binder phase lamellaeis present in all tested inserts, given by a clear increase in number of lamellae in the microstructure of a tested cutting edge compared to a pristine cutting edge ofthe same material. The lamellae formation is discussed and can be explained by the stresses experienced by the cutting edge during turning. The importance of good coating adhesion was shown by formation of cavities in inserts that experienced akiflng of the coating.

  • 32. Weidow, Jonathan
    et al.
    Blomqvist, Andreas
    Salomonsson, Johanna
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Cemented carbides based on WC pre-alloyed with Cr or Ta2015In: INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, ISSN 0263-4368, Vol. 49, p. 36-41Article in journal (Refereed)
    Abstract [en]

    WC powder pre-alloyed with Ta or Cr was used to produce WC-Co based cemented carbides and these were compared with materials produced from pure WC. Atom probe tomography analysis of the pre-alloyed as-sintered materials showed that a high, non-uniform, concentration of Ta or Cr remained in the WC lattice after sintering. The hexagonal (W,Ta)C partially decomposes during sintering leading to the formation of a fcc MC phase. Similarly, the (W,Cr)C partially decomposes, but no Cr-rich precipitates were observed in either of the Cr containing samples. The hardness of the crystallites of the doped materials was significantly lower than the undoped WC, as measured by nano-indentation. The Young's moduli of the doped crystals were significantly lower than the undoped WC in agreement with the lowering of the elastic constants, from ab initio calculations. The microhardness (HV) reflected what would be expected from the average WC grain size giving that the grain boundary surface area is more important for the material hardness than the hardness of the WC crystals themselves in the investigated grain size range.

  • 33.
    Yildiz, Ahmet Bahadir
    et al.
    KTH Royal Inst Technol, Dept Mat Sci & Engn, SE-10044 Stockholm, Sweden.
    Weidow, Jonathan
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden.
    Ryukhtin, Vasyl
    Nucl Phys Inst, Cp 130, Husinec Rez 25068, Czech Republic.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Sandvik, SE-12680 Stockholm, Sweden.
    Wahnstrom, Goran
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden.
    Hedstrom, Peter
    KTH Royal Inst Technol, Dept Mat Sci & Engn, SE-10044 Stockholm, Sweden.
    Very-small angle neutron scattering study on grain coarsening inhibition by V-doping of WC-Co composites2019In: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 173, p. 106-109Article in journal (Refereed)
    Abstract [en]

    The mechanical properties of cemented carbides can be tuned by controlling WC grain coarsening and the simultaneous growth of the binder pocket size during the sintering. So far, bulk studies considering this phenomenon are scarce, but here, we report the first very-small angle neutron scattering (VSANS) study on cemented carbides. VSANS is supplemented with electron backscatter diffraction (EBSD) and the microstructural refinement by increasing V-doping (0, 0.02, 022, and 0.76 wt%) is quantified. The capability of VSANS as a non-destructive bulk probe for cemented carbides is shown, paving way for forthcoming in-situ studies.

1 - 33 of 33
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