Tailoring phase transformation and precipitation features in a Al_(21)Co_(19.5)Fe_(9.5)Ni_(50)eutectic high-entropy alloy to achieve different strength-ductility combinations  

作　　者：Xudong Liu Haoxiang Liu Yuhao Wu Mingyang Li Chenxu Xing Yixuan He 

机构地区：[1]Collaborative Innovation Center of NPU,Shanghai 201108,China [2]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China [3]Center of Advanced Lubrication and Seal Materials,Northwestern Polytechnical University,Xi’an 710072,China [4]Institute of Superconducting Materials and Applied Technology,Northwestern Polytechnical University,Xi’an 710072,China

出　　处：《Journal of Materials Science & Technology》2024年第28期111-125,共15页材料科学技术(英文版)

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).

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.

关 键 词：Eutectic high-entropy alloys L1_(0)phases Cooling rate Deformation mechanisms Strength-ductility combination 

分 类 号：TG1[金属学及工艺—金属学]