Anisotropic analysis of dislocation line energies and possible dislocation core dissociations in MoSi₂

Abstract

Abstract The line energy factors of(110)[001], [331], [11],[11];(100)[010];(103)[331], [010]; and (011)[100], [111] dislocations as well as the elastic interaction forces between two 1/4<331] and two 1/4<111] partials, in MoSi2, are calculated using anisotropic elasticity theory. The line energy factors are found to be relatively large (170–250 GPa) and isotropic, whereas the non-radial interaction forces are found to be a small fraction of the radial forces. The atomic configurations around planar faults on the {110), {013) and {116) planes are analysed using the embedded atom method technique. Results of such calculations are used to energetically rank the possible core dissociations of 1/2<331], 1/2<111], <110], and <100] dislocations on the {110), {013) amd {116) planes in MoSi2. Collectively, these results suggest that the core structures of 1/2<331], 1/2<111], <110] and <100] dislocations are expected to be complicated and non-planar, similar to dislocation cores in b.c.c derivative B2 structures. The results indicate that there is little a priori reason to believe that dislocation core transformation locking events occur on 1/2<331] screw dislocations lying on {110) planes; unlike the locking events occurring on <101> screws lying on {111} planes in L10 and L12 structures. Electronic structure calculations of planar fault energies as well as atomistic simulations of mobilities of various dislocations are required to understand the fundamentals of the compressive deformation behaviour of MoSi2.