摘要
Eutectic high-entropy alloys(EHEAs)that combine the advantages of HEAs and eutectic alloys are promising materials for high-temperature environments.However,the mechanical properties of currently developed EHEAs still cannot meet the servicing requirements.Here,we propose a strategy to optimize the tensile properties in a Al_(21)Co_(19.5)Fe_(9.5)Ni_(50)EHEA by regulating the phase transformation and precipitation features.The results showed that the as-cast Al_(21)Co_(19.5)Fe_(9.5)Ni_(50)EHEA mainly consists of face-centered cubic(FCC)and B2 phases showing a lamellar morphology,and the FCC and B2 phases keep a stable K-S orientation relationship.Solution treatment at 900 and 1100°C followed by furnace cooling to room temperature leads to a significant precipitation of L1_(2)phases within the FCC phases.In the subsequent tensile deformation process,dispersed L1_(2)phases and the transformation from B2 to L1_(0)phases can significantly enhance the yield strength of the designed EHEA.Furthermore,solution treatment at the same temperature,followed by rapid water quenching,results in the appearance of numerous L1_(0)phases within the B2 phases.The transformation from L1_(0)to B2 phases during subsequent tensile deformation can make the B2 and FCC phases return to a K-S orientation relationship.This,in turn,reduces the tendency for dislocation pile-ups at the phase interfaces and improves the ductility.We believe that this work will provide some new references for designing EHEAs with excellent mechanical properties.
基金
supported by the funds of the Shanghai Sailing Program,the National Natural Science Foundation of China(No.52104386)
the Xi’an Association for Science and Technology Young Talents Lifting Program,and the State Key Laboratory of Solidification Processing(NPU),China(No.2022-TS-08).
作者简介
Corresponding author at:Yixuan He,Collaborative Innovation Center of NPU,Shanghai 201108,China.E-mail address:.yxhe@nwpu.edu.cn。
