uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Toller, Lisa
Alternative names
Publications (10 of 12) Show all publications
Toller-Nordström, L., Mingard, K. & Norgren, S. (2019). Deformation induced martensite in a Fe-Ni-Co binder phase of a hardmetal. Materials Characterization, 155, Article ID 109783.
Open this publication in new window or tab >>Deformation induced martensite in a Fe-Ni-Co binder phase of a hardmetal
2019 (English)In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 155, article id 109783Article in journal (Refereed) Published
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.

Keywords
Hardmetal, Deformation, Diffraction, Electron microscopy, Martensite
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:uu:diva-394261 (URN)10.1016/j.matchar.2019.06.025 (DOI)000483411900015 ()
Funder
Vinnova, Co-2014-01916
Available from: 2019-10-11 Created: 2019-10-11 Last updated: 2019-10-22Bibliographically approved
Toller-Nordström, L. (2019). Insights into wear and deformation of alternative binder hardmetals. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Insights into wear and deformation of alternative binder hardmetals
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This work presents new insights into how hardmetals with alternative binders as well as cobalt based references react to wear and deformation. The main focus has been on hardmetals for steel turning, but also on studying certain fundamental properties of the new binder materials.

Cobalt has traditionally been the most common binder phase for tungsten carbide grains in hardmetals, but recent insights into the carcinogenicity of cobalt powder has led to a need to research alternatives. In this work hardmetals with binder phases consisting of alloys of iron and nickel or iron, nickel and cobalt have been studied.

Coated hardmetal inserts used until end of tool life in steel turning have been evaluated with respect to the plastic deformation and coating adhesion. It was found that grain boundary sliding of tungsten carbide/tungsten carbide grain boundaries is an important deformation mechanism during dry face turning, concluded based on an increased number of binder phase lamellae in tungsten carbide/tungsten carbide grain boundaries in the deformed microstructure.  The lamellae were found to have a preferred orientation, coinciding with the expected flow of material during deformation.

For turning inserts with exposed hardmetal due to flaked coating it was further observed that the microstructure contained cavities caused by the increased temperature of the hardmetal when the protective coating layers are lost. No cavities were found in samples which were still covered by coating at the end of a test. It was therefore concluded that improving the coating adhesion is an important step towards improved performance of alternative binder hardmetals.

Some of the alternative binders in this work were iron rich alloys. Alloys rich in iron can be either austenitic, martensitic or a mixture of the two and this will have a large influence on the final hardmetal properties. It is also possible to make an iron rich alloy which is austenitic at room temperature, but forms deformation induced martensite as a response to stress or strain. This work investigated deformation induced martensite formed during scratching and in abrasive wear of a binder phase alloy of iron, nickel and cobalt. Electron diffraction in both scanning electron microscopes and transmission electron microscopes showed that scratching the surface of this hardmetal resulted in a finely grained surface layer of mixed austenite and martensite. This could prove beneficial in applications.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2019. p. 77
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1873
Keywords
hardmetal, cemented carbide, alternative binders, steel turning, electron microscopy, electron diffraction
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
urn:nbn:se:uu:diva-395619 (URN)978-91-513-0789-3 (ISBN)
Public defence
2019-12-06, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Opponent
Supervisors
Available from: 2019-11-14 Created: 2019-10-22 Last updated: 2019-11-14
Wiklund, U., Emy, G., Grandin, M. & Toller, L. (2019). Wear mechanisms of tools for exploration drilling. In: Euromat 2019, Stockholm, Sweden: . Paper presented at Euromat 2019, European congress and exhibition on materials and processes, Stockholm, Sweden, September 1-5, 2019 (pp. 787).
Open this publication in new window or tab >>Wear mechanisms of tools for exploration drilling
2019 (English)In: Euromat 2019, Stockholm, Sweden, 2019, p. 787-Conference paper, Oral presentation with published abstract (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-393039 (URN)
Conference
Euromat 2019, European congress and exhibition on materials and processes, Stockholm, Sweden, September 1-5, 2019
Available from: 2019-09-13 Created: 2019-09-13 Last updated: 2019-09-13
Toller, L. (2017). Alternative binder hardmetals for steel turning. (Licentiate dissertation). Uppsala: Uppsala University
Open this publication in new window or tab >>Alternative binder hardmetals for steel turning
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The goal of this work is to understand how the wear and deformation mechanisms of hardmetalinserts change when the cobalt binder phase is replaced with a dierent metal or analloy. The focus is on inserts for steel turning. The work presented in this licentiate thesisconsists of the rst steps.Cobalt is the most common binder phase in hardmetal tools based on tungsten carbide asthe hard phase. Metallic cobalt powder, present during the manufacturing, has been associatedwith lung diseases and an increased risk for lung cancer if inhaled. Therefore it is importantto investigate alternative binders as one possible solution.This work studies binder phase alloys from the iron-nickel-cobalt system. These alloyscan be either austenitic, martensitic or a mixture of the two phases. By changing the binderphase composition to change the crystal structure it is possible to tailor the macroscopic mechanicalproperties of the material. It is also possible to tailor the composition in such a waythat the binder is transformation toughening, forming martensite as a response to mechanicaldeformation.The majority of inserts for steel turning are coated, and it is important to investigate if thehardmetals with alternative binder can be coated and if the coating adhesion is sucient forsteel turning.Four dierent alternative binder alloys and one reference with cobalt binder coated bychemical vapour deposition were investigated by scratch testing to determine the adhesion.The scratch test adhesion was sucient on all samples, but signicant variations in coatingadhesion were found.One alternative binder with 86wt%Ni and 14wt%Fe and a reference with cobalt binder manufacturedto mimic state of the art turning inserts were tested in steel turning. The alternativebinder grades had a lower resistance to plastic deformation and this was attributed to earlyaking of the coating due to a lower coating adhesion. Focused ion beam and scanning electronmicroscopy were used to study the deformation of the hard metal in the used cuttinginserts.

Place, publisher, year, edition, pages
Uppsala: Uppsala University, 2017. p. 54
Keywords
hardmetal, cemented carbide, alternative binder, steel turning, scratch testing, plastic deformation, EBSD, transformation toughening
National Category
Materials Engineering
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
urn:nbn:se:uu:diva-332451 (URN)
Presentation
2017-01-25, Å2001, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2017-10-27Bibliographically approved
Toller, L., Liu, C., Holmström, E., Larsson, T. & Norgren, S. (2017). Investigation of Cemented Carbides with Alternative Binders after CVD Coating. International journal of refractory metals & hard materials, 62, 225-229
Open this publication in new window or tab >>Investigation of Cemented Carbides with Alternative Binders after CVD Coating
Show others...
2017 (English)In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 62, p. 225-229Article in journal (Refereed) Published
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.

Keywords
alternative binders, cemented carbide, CVD
National Category
Engineering and Technology Materials Engineering
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
urn:nbn:se:uu:diva-310617 (URN)10.1016/j.ijrmhm.2016.07.005 (DOI)000390503200019 ()
Available from: 2016-12-16 Created: 2016-12-16 Last updated: 2018-09-17Bibliographically approved
Toller, L., Jacobson, S. & Norgren, S. (2017). Life time of cemented carbide inserts with Ni-Fe binder in steel turning. Wear, 376, 1822-1829
Open this publication in new window or tab >>Life time of cemented carbide inserts with Ni-Fe binder in steel turning
2017 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 376, p. 1822-1829Article in journal (Refereed) Published
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.

Keywords
Cutting tools, Cemented carbide, Alternative binder, Face turning
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-329133 (URN)10.1016/j.wear.2017.02.018 (DOI)000403902000097 ()
Funder
VINNOVA
Available from: 2017-10-10 Created: 2017-10-10 Last updated: 2019-10-22Bibliographically approved
Toller, L. & Norgren, S. (2017). Mechanisms of plastic deformation in WC-Co and WC-Ni-Fe turning inserts. In: : . Paper presented at 19th Plansee Seminar 2017.
Open this publication in new window or tab >>Mechanisms of plastic deformation in WC-Co and WC-Ni-Fe turning inserts
2017 (English)Conference paper, Oral presentation with published abstract (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.

Keywords
hardmetal, turning, alternative binder, deformation mechanism, grain boundary sliding
National Category
Engineering and Technology Materials Engineering
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
urn:nbn:se:uu:diva-332453 (URN)
Conference
19th Plansee Seminar 2017
Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2017-12-29Bibliographically approved
Toller, L., Larsson, T., Jacobson, S. & Norgren, S. (2015). CVD Coating Adhesion on Metal Cutting Insertswith Alternative Binders. In: : . Paper presented at Wear of Materials 2015, Toronto.
Open this publication in new window or tab >>CVD Coating Adhesion on Metal Cutting Insertswith Alternative Binders
2015 (English)Conference paper, Poster (with or without abstract) (Other academic)
Keywords
metal cutting, alternative binder, CVD, scratch test, adhesion
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-268291 (URN)
Conference
Wear of Materials 2015, Toronto
Available from: 2015-12-10 Created: 2015-12-03 Last updated: 2016-01-07
Toller, L., Liu, C., Holmström, E., Larsson, T. & Norgren, S. (2015). Investigation of Cemented Carbides with Alternative Binders after CVD Coating. In: : . Paper presented at Euro PM 2015, Reims.
Open this publication in new window or tab >>Investigation of Cemented Carbides with Alternative Binders after CVD Coating
Show others...
2015 (English)Conference paper, Oral presentation with published abstract (Refereed)
Keywords
alternative binders, CVD, metal cutting, hard metal
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Materials Analysis
Identifiers
urn:nbn:se:uu:diva-268290 (URN)
Conference
Euro PM 2015, Reims
Available from: 2015-12-10 Created: 2015-12-03 Last updated: 2015-12-16
Toller-Nordström, L., Gee, M., Holmberg, A., Mingard, K., Lilja, M. & Norgren, S. Abrasive wear of hardmetals with a binder phase forming deformation induced martensite.
Open this publication in new window or tab >>Abrasive wear of hardmetals with a binder phase forming deformation induced martensite
Show others...
(English)Manuscript (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.

Keywords
hardmetal, alternative binders, cemented carbides, rock drilling, microscale abrasion, micro scratch testing
National Category
Engineering and Technology Materials Engineering
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
urn:nbn:se:uu:diva-395618 (URN)
Available from: 2019-10-22 Created: 2019-10-22 Last updated: 2019-11-06
Organisations

Search in DiVA

Show all publications