Fig. 3: Local and global chemistry effects on stacking-fault energies.
From: Insights into the anomalous hardness of the tantalum carbides from dislocation mobility
a Illustration of the primary vacancy-ordered C2/m M6C5 structure investigated in this work, with the position of an M6C5 quasi-molecule within the host B1 structure shown below. Metal atoms are indicated by magenta markers, carbon atoms are indicated by blue markers, and empty circles represent structural carbon vacancies. The slip plane for the shown GSF energy curves lies between L3 and the underlying metal {111}B1 layer. b View from \({\left\langle 111\right\rangle }_{{{{\rm{B}}}}1}\) direction of vacancy ordering in the structure shown in (a), with a representative cell defined by blue arrows. c Variation in \(\left\langle 112\right\rangle {\left\{111\right\}}_{{{{\rm{B}}}}1}\) GSF energies observed with selective filling of the carbon-depleted planes labeled in (a), showing relatively localized effect of vacancy filing on the ISF energy (the metastable point at the \(\delta /b=2\sqrt{3}/3\) location on each curve). All disregistry values are shown in units of the perfect dislocation Burgers vector magnitude b. d View from \({\left\langle 111\right\rangle }_{{{{\rm{B}}}}1}\) direction of vacancy ordering in the alternative-ordered M6C5 structure. e GSF energy curve for \(\left\langle 112\right\rangle {\left\{111\right\}}_{{{{\rm{B}}}}1}\) in M6C5 with alternative vacancy ordering, showing little variation in ISF energy due to particular ordering of carbon vacancies.
