Physical and mechanical properties of single crystals of the Mo5Si3C phase

High purity single crystals of the Mo5Si3C phase with the D88 type structure have been grown and their physical and mechanical properties have been measured. The composition of single crystals is Mo4.66Si3.00C0.402. Lattice constants of the compound are a=0.7286 nm and c=0.5046 nm. Vickers micro-hardness and fracture toughness are 13.4 MPa and 1.3 MPa m1/2, respectively. The anisotropy ratio of thermal expansion coefficient (αc/αa) of the compound is approximately 2 at 773 K. In contrast, the elastic properties for the compound are nearly isotropic. The deformation behavior of the compound has been studied in compression using [0001], [1340], [2249] oriented single crystals. These single crystals can be deformed plastically at temperatures higher than 1573 K. Slip occurs on {0001}<11 ̄20> and an unidentified non-basal system.