Effect of lamellae orientation on tensile properties of directionally solidified Ti–46Al–0.5W–0.5Si alloy

For full-lamellar TiAl alloys, mechanical properties can be improved in a wide range of temperature by controlling lamellar orientation parallel to growth direction. However, lamellar controlled TiAl alloys with good properties and large scale are difficult to obtain due to sever interface reaction between TiAl melts and mould materials. In this paper, effect of lamellar orientation on tensile properties of directionally solidified (DS) Ti-46Al-0.5W-0.5Si alloy using oxide ceramics crucible was investigated. DS alloys with parallel lamellar structure had better tensile strength (479MPa) and elongation (0.76%) than that of specimen with equiaxed grains (428MPa, 0.22%). Fracture modes of DS alloys were interlamellar, translamellar mode and both, which depended on the lamellae orientation.