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

Abstract

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.

KEYWORDS:

• TiAl intermetallics
• directional solidification
• lamellar orientation
• mechanical property
• fracture behaviour

Acknowledgements

This work was supported by the Young Teachers Training Program of Henan Province Higher Education Institutions (Grant Number 2018GGJS090); the National Natural Science Foundation of China (Grants Numbers 51501167 and U1904175); Zhengzhou Major Science and Technology Innovation Project (Grant Number: 2019CXZX0065). JL Fan thanks Dr Zhang Yuan for the preparation of fracture surface specimens.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Young Teachers Training Program of Henan Province Higher Education Institutions: [Grant Number 2018GGJS090]; Zhengzhou Major Science and Technology Innovation Project: [Grant Number 2019CXZX0065]; National Natural Science Foundation of China: [Grant Number U1904175]; National Natural Science Foundation of China: [Grant Number 51501167].