Orientation relationship between bcc precipitates and Ti5Si3 matrix in Mo–Si–B–Ti–C quinary alloys

In this study, the crystallographic orientation relationship between bcc precipitates and a Ti5Si3 matrix in Mo–50Ti–14Si–6C–6B (at.%) alloy was established. The alloy microstructure consisted of the bcc solid solution, Ti5Si3, Mo5SiB2, and TiC phases. The metal-rich Ti5Si3 phase was formed during a solidification stage, followed by the precipitation of the bcc phase within the Ti5Si3 matrix in the subsequent annealing process. The orientation relationship between the two phases was described by the expression: 112 bcc / / 01 1 ‾ 0 Ti 5 Si 3 and 3 ‾ 11 bcc / / 0001 Ti 5 Si 3 . The formation of a low-energy interface between the two phases was explained by the edge-to-edge matching of their corresponding lattice planes at the faceted interface.