Cu-based shape memory alloys(SMAs)show great potential in the application of high temperature,but their performance improvement combining with additive manufacturing is still challenging.In this paper,nearly defect-fr...Cu-based shape memory alloys(SMAs)show great potential in the application of high temperature,but their performance improvement combining with additive manufacturing is still challenging.In this paper,nearly defect-free(99.7%relative density)CuAlNi SMAs with two types of thermal-induced martensites,18R and 2H,were successfully fabricated by laser powder bed fusion(LPBF).The remelting printing strat-egy with systematic optimization framework including densification and printability analysis was used to get optimal process window.The twin-related self-accommodation structure with long period stacking order substructure was formed during additive manufacturing process.The as-build samples show excel-lent mechanical properties(ultimate compressive strength of 1593±10 MPa and large fracture strain of 23.0%±0.1%)with double-yielding,and outstanding shape memory effect,with maximum recoverable strain of 3.39% and nearly 100%recovery rate under compressive strain not exceeding 6%.Furthermore,the microstructural evolution in LPBF involving remelting,martensitic transformation,and 2H marten-site was discussed.This result not only builds the microstructure framework involving high reflectivity alloys and martensitic transformation but also provides insight into the applicability of LPBF process in producing Cu-based SMAs.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(No.52275365).
文摘Cu-based shape memory alloys(SMAs)show great potential in the application of high temperature,but their performance improvement combining with additive manufacturing is still challenging.In this paper,nearly defect-free(99.7%relative density)CuAlNi SMAs with two types of thermal-induced martensites,18R and 2H,were successfully fabricated by laser powder bed fusion(LPBF).The remelting printing strat-egy with systematic optimization framework including densification and printability analysis was used to get optimal process window.The twin-related self-accommodation structure with long period stacking order substructure was formed during additive manufacturing process.The as-build samples show excel-lent mechanical properties(ultimate compressive strength of 1593±10 MPa and large fracture strain of 23.0%±0.1%)with double-yielding,and outstanding shape memory effect,with maximum recoverable strain of 3.39% and nearly 100%recovery rate under compressive strain not exceeding 6%.Furthermore,the microstructural evolution in LPBF involving remelting,martensitic transformation,and 2H marten-site was discussed.This result not only builds the microstructure framework involving high reflectivity alloys and martensitic transformation but also provides insight into the applicability of LPBF process in producing Cu-based SMAs.
