A theoretical investigation of the slip systems of Ta2C

Tantalum carbides show a wide range of interesting properties including plasticity at elevated temperatures. In a companion paper, the plastic deformation of high-temperature polycrystalline Ta2C was examined using transmission electron microscopy. Here, we investigate the different potential slip systems in α-Ta2C using density functional theory to compute generalized stacking fault (GSF) energy curves. The GSF curves show that the preferred slip system is the basal plane. The results further show that slip occurs preferentially between the Ta-Ta layers, or between metal-metal bonds. GSF energy curves for the basal, prismatic and pyramidal planes show a hierarchy of preferred slip systems and pyramidal slip is likely enabled by the high temperature and the need for additional slip systems caused by the general deformation. These results are not only useful in understanding deformation in α-Ta2C but can be used to understand plasticity in general transition metal hemicarbides.