Physical and mechanical properties of single crystals of the Mo 5Si 3C phase

Abstract

High purity single crystals of the Mo 5Si 3C phase with the D8 8 type structure have been grown and their physical and mechanical properties have been measured. The composition of single crystals is Mo 4.66Si 3.00C 0.402. 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 m 1/2, respectively. The anisotropy ratio of thermal expansion coefficient ( α c/ α a) 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], [13 4 0], [22 4 9] oriented single crystals. These single crystals can be deformed plastically at temperatures higher than 1573 K. Slip occurs on {0001}<11 ̄ 2 0> and an unidentified non-basal system.