High strength Al_(0.7)CoCrFeNi_(2.4)hypereutectic high entropy alloy fabricated by laser powder bed fusion via triple-nanoprecipitation  

作　　者：Zhaowen Geng Chao Chen Miao Song Jinru Luo Jiaxuan Chen Ruidi Li Kechao Zhou 

机构地区：[1]Cent South Univ,State Key Lab Powder Met,Changsha,410083,China [2]Suzhou Laboratory,Suzhou,215004,China

出　　处：《Journal of Materials Science & Technology》2024年第20期141-155,共15页材料科学技术（英文版）

基　　金：The authors would like to acknowledge experimental help and invaluable discussions from Shanzi Yu,Xianglong Li,Zhongliang Shu,Shichao Liu,Ruifeng Xu,Pengda Niu,Dan Li,Rou Ding,Min Liu,Haoyang Li,and Taomei Zhang.The authors would also like to acknowledge the financial support from the Natural science foundation of China(No.52271046,No.52171052);the Natural Science Foundation of Hunan Province,China(No.2022JJ20061,No.2023JJ30684);the Key R&D Program of Guangdong Province,China(No.2019B010943001);the Transformation and Industrializa-tion Plan of Scientific and Technological Achievements of Hunan Province,China(No.2020GK2031);the National Natural Science Foundation of China(No.52171052);the funding from State Key Laboratory of Powder Metallurgy,Central South University;the Fundamental Research Funds for the Central Universities of Central South University.

摘　　要：Eutectic high-entropy alloys,composed of FCC/B2 phases with a narrow solidification interval and excel-lent fluidity,have become a new hotspot in additive manufacturing.Nevertheless,their microstructures exhibit significant sensitivity to processing parameters,feedstocks,and composition,ultimately limiting the alloys’engineering applications.Here,a hypereutectic Al_(0.7)CoCrFeNi_(2.4)alloy with a low cracking sus-ceptibility index was designed by Thermo-Calc calculation and fabricated by laser powder bed fusion.Results show that the as-printed Al_(0.7)CoCrFeNi_(2.4)alloy manifests a stable cellular structure,coupled with appreciable ultimate tensile strength(≥1200 MPa)and ductility(≥20%)over a wide range of process-ing parameters.After aging at 800℃for 30 min,outstanding strength(1500 MPa)and elongation(15%)were obtained.Considerable mechanical properties after aging stem from a triple strengthening mecha-nism,i.e.,L1_(2) nanoprecipitates and rod-shaped B2 particles within the FCC matrix,along with Cr-enriched spherical nanoparticles in the B2 phase.Meanwhile,hierarchical structure,i.e.,FCC dominated matrix,a discontinuous B2 phase,a precipitation-free zone in the B2 phase,and a K-S orientation relationship be-tween FCC and B2,facilitate to maintain excellent plasticity.These results guide designing HEAs by AM with controllable microstructures and outstanding mechanical properties for industrial applications.

关 键 词：Laser powder bed fusion HYPEREUTECTIC High entropy alloys NANOPRECIPITATION Strengthening mechanism 

分 类 号：TG14[一般工业技术—材料科学与工程]