Dislocation-Mediated Plasticity in the Intermetallic Smco5 Phase

Abstract

The intermetallic SmCo5 phase is well known for its unique magnetic properties, but so far, research on the mechanical properties and the underlying lattice defects is comparably scarce. This study aims to investigate the deformation mechanisms of the SmCo5 phase through nanoindentation and micropillar compression on two single crystals with different orientations. We find two active slip systems in compression, the pyramidal slip system {2 111} ‹2 1 1 6› and the basal slip system (0 0 0 1) [2 11 0]. Additionally, basal and pyramidal stacking faults and partial dislocations were observed by transmission electron microscopy. Using ab initio and atomistic modelling we investigated the underlying defect structures and energy barriers. These allowed us to rationalize the observed slip systems and suggest that the pyramidal stacking faults may form by a synchro-shear slip mechanism. Our findings also provide a basis to understand the deformation behaviour of structurally related phases in the Sm-Co system, such as Sm2Co7, which comprises SmCo5 and Laves SmCo2 building blocks.

Keywords: SmCo5, deformation behaviour, nanoindentation, micropillar compression, TEM, atomistic simulation, DFT