文献类型：期刊文献

英文题名：Unusual deformation substructure and strain hardening in an additively manufactured CoCrFeMnNi high entropy alloy under high-velocity impact loading

作者：Chen, Hongyu[1];Yang, Xiaofeng[2];Gu, Dongdong[1];Liu, Yang[3];Yang, Shengze[3];Chen, Xiyu[2];Kosiba, Konrad[4];Chen, Yufei[2];Du, Junhang[2];Prashanth, Konda Gokuldoss[5,6];Wang, Yonggang[3];Lu, Tiwen[2]

机构：[1]Nanjing Univ Aeronaut & Astronaut, Coll Mat Sci & Technol, Jiangsu Prov Engn Res Ctr Laser Addit Mfg High Per, Nanjing 210016, Peoples R China;[2]East China Univ Sci & Technol, Key Lab Pressure Syst & Safety, State Key Lab Chem Safety, Minist Educ, Shanghai 200237, Peoples R China;[3]Ningbo Univ, Key Lab Impact, Safety Engn Minist Educ China, Ningbo 315211, Peoples R China;[4]Leibniz Inst Solid State & Mat Res Dresden, Inst Mat Chem, 12 Helmholtzstr 20, D-01069 Dresden, Germany;[5]Tallinn Univ Technol, Dept Mech & Ind Engn, EE-19086 Tallinn, Estonia;[6]Vellore Inst Technol, CBCMT, Vellore 632014, Tamil Nadu, India

年份：2026

卷号：241

起止页码：35

外文期刊名：JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY

收录：;EI(收录号：20252118488869);WOS:【SCI-EXPANDED(收录号:WOS:001501434300002)】；

基金：This work was financially supported by the National Key Research and Development Program (No. 2022YFB4602100) , National Natural Science Foundation of China (Nos. 52205152 , 12402456 , 52375347 , and U21B2077) , open project of State Key Laboratory of Chemical Safety (No. SKLCS-2024010) , Zhejiang Provincial Natural Science Foundation of China (No. LQ23E050010) , Shanghai Pujiang Program (No. 3PJD023) , and Natural Science Foundation of Ningbo (Nos. 2023J008 and 2024J046) .

语种：英文

外文关键词：Laser powder bed fusion; High entropy alloy; Dynamic loading; Cellular structure; Twinning behavior

摘要：The superior dynamic mechanical properties of high-entropy alloys (HEAs) have attracted great interest, while there have been limited studies on the adiabatic temperature change as well as the deformation mechanism in the additively manufactured HEAs under impact loading. In this work, the deformation mechanism of laser powder bed fusion (LPBF)-fabricated CoCrFeMnNi HEAs under high-velocity impact loading was elucidated through multiple microstructural characterization in conjunction with molecular dynamics simulation. Different from CoCrFeMnNi alloys made by thermomechanical processing, both yield strength (YS) and strain hardening behavior of LPBF-fabricated HEA samples are more sensitive to the strain rate in the range of 0.001/s to 50 0 0/s. The YS of the LPBF-fabricated HEAs shows an increasing trend from similar to 452 MPa at 0.001/s to similar to 685 MPa at 50 0 0/s. The strain hardening capacity also increases with the increase of strain rate from 0.001/s to 3000/s. When the strain rates are over 30 0 0/s, high strain hardening capacity is derived from strong dislocation multiplication induced by a high density of deformation twin boundaries. An intriguing mechanical response of the LPBF-fabricated HEAs emerges during loading: the strain hardening rate slightly decreases when the strain rate values increase from 30 0 0/s to 50 0 0/s, which is ascribed to the potential temperature rise-induced dislocation dynamic recovery. Further, in comparison to as-cast HEAs, LPBF-fabricated HEAs show significantly enhanced twinning behavior at high strain rates. The difference is related to unique as-printed microstructure of LPBF-fabricated HEAs: high-density dislocation increasing flow stress, cellular boundaries inducing dislocation dissociation and subsequent nano-twins at high strain rates. These substructures bring enhanced twinning behavior and strain rate-dependent high-velocity impact behavior in LPBF-fabricated HEAs. Our work provides a new insight into the dynamic impact behavior of additively manufactured HEA materials. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.