Electronic structure and shearing in nanolaminated ternary carbides
2006 (English)In: Solid State Communications, ISSN 0038-1098, E-ISSN 1879-2766, Vol. 139, no 4, 139-143 p.Article in journal (Refereed) Published
We have studied shearing in M2AlC phases (M = Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W) using ab initio calculations. We propose that these phases can be classified into two groups based on the valence electron concentration induced changes in C-44. One group comprises M = VB and VIB, where the C-44 values are approximately 170 GPa and independent of the corresponding MC. The other group includes M = IIIB and IVB, where the C-44 shows a linear dependency with the corresponding MC. This may be understood based on the electronic structure: shear resistant bands are filled in M2AlC phases with M = VB and VIB, while they are not completely filled when M = IIIB and IVB. This notion is also consistent with our stress-strain analysis. These valence electron concentration induced changes in shear behaviour were compared to previously published valence electron concentration induced changes in compression behaviour [Z. Sun, D. Music, R. Ahuja, S. Li, J.M. Schneider, Phys. Rev. B 70 (2004) 092102]. These classification proposals exhibit identical critical valence electron concentration values for the group boundary. However, the physical mechanisms are not identical: the classification proposal, for the bulk modulus is based on MC-A coupling, while shearing is based on MC-MC coupling.
Place, publisher, year, edition, pages
2006. Vol. 139, no 4, 139-143 p.
M2AlC phases, shearing, ab initio calculations
IdentifiersURN: urn:nbn:se:uu:diva-155433DOI: 10.1016/j.ssc.2006.06.007ISI: 000239875700001OAI: oai:DiVA.org:uu-155433DiVA: diva2:426064