摘要
The L1_(2)-strengthened Co_(34)Cr_(32)Ni_(27)Al_(4)Ti_(3)medium-entropy alloy(MEA)with precipitations of grain boundaries has been developed through selective laser melting(SLM)followed by cold rolling and annealing,exhibiting excellent strength-ductility synergy.The as-printed alloy exhibits low yield strength(YS)of~384 MPa,ultimate tensile strength(UTS)of~453 MPa,and uniform elongation(UE)of 1.5%due to the existence of the SLM-induced defects.After cold rolling and annealing,the YS,UTS,and UE are significantly increased to~739 MPa,~1230 MPa,and~47%,respectively.This enhancement primarily originates from the refined grain structure induced by cold rolling and annealing.The presence of coherent sphericalγ'precipitates(L1_(2)phases)and Al/Ti-rich precipitates at the grain boundaries,coupled with increased lattice defects such as dislocations,stacking faults,and ultrafine deformation twins,further contribute to the property’s improvement.Our study highlights the potential of SLM in producing high-strength and ductile MEA with coherent L1_(2)nanoprecipitates,which can be further optimized through subsequent rolling and annealing processes.These findings offer valuable insights for the development of high-performance alloys for future engineering applications.
基金
This work is supported by the National Natural Science Foundation of China(Nos.51971180,52271037,and 51971179)
the Guangdong Provincial Science and Technology Program,China(No.2019B090905009)
the Shaanxi Provincial Science and Technology Program,China(No.2023-JC-ZD-23)
the Foreign Senior Talents Program of Guangdong Province,China,and the Fundamental Research Funds for the Central Universities of China(No.D5000230131)
the Shenzhen Fundamental Research Program(Grant No.JCYJ20210324122203010).The authors would like to express their sincere gratitude to Dr.W.Loeser and Dr.V.Y.Zadorozhnyy for invaluable discussion.
