文献类型：期刊文献

英文题名：Additively manufactured high strength and ductility CrCoNi medium entropy alloy with hierarchical microstructure

作者：Han, Bolun[1,2];Zhang, Chengcheng[1,2];Feng, Kai[1,2,3,4];Li, Zhuguo[1,2];Zhang, Xiancheng[5];Shen, Yao[6];Wang, Xiaodong[6];Kokawa, Hiroyuki[1,2,7];Li, Ruifeng[8];Wang, Zhiyuan[1,2];Chu, Paul K.[3,4]

机构：[1]Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, Shanghai Key Lab Mat Laser Proc & Modificat, Shanghai 200240, Peoples R China;[2]Collaborat Innovat Ctr Adv Ship & Deep Sea Explor, Shanghai 200240, Peoples R China;[3]City Univ Hong Kong, Dept Phys, Kowloon, Tat Chee Ave, Hong Kong, Peoples R China;[4]City Univ Hong Kong, Dept Mat Sci & Engn, Kowloon, Tat Chee Ave, Hong Kong, Peoples R China;[5]East China Univ Sci & Technol, Sch Mech & Power Engn, Key Lab Pressure Syst & Safety, Minist Educ, Shanghai 200237, Peoples R China;[6]Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China;[7]Tohoku Univ, Dept Mat Proc, Sendai, Miyagi 9808579, Japan;[8]Jiangsu Univ Sci & Technol, Sch Mat Sci & Engn, Zhenjiang 212003, Jiangsu, Peoples R China

年份：2021

卷号：820

外文期刊名：MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

收录：;EI(收录号：20212510522602);WOS:【SCI-EXPANDED(收录号:WOS:000668738400001)】；

基金：This work was financially supported by National Key R&D Program of China (No. 2018YFB0407300) , National Natural Science Foundation of China (Grant No. 51971144) , Natural Science Foundation of Shanghai (Grant No.19ZR1425200) , Shenzhen - Hong Kong Innovative Collaborative Research and Development Program CityU 9240014, GuangdongHong Kong Technology Cooperation Funding Scheme (TCFS) GHP/085/18SZ (CityU 9440230) , and Hong Kong Innovation and Technology Fund (ITF) ITS/452/17FP (CityU 9440179) . Special thanks go to the Shanghai Synchrotron Radiation Facility for providing the advanced characterization devices and techniques for the SXRD tests, IAC in SJTU for the support in multiscale characterization and Prof. Yan Cai in SJTU for the support in cryogenic mechanical tests.

语种：英文

外文关键词：Selective laser melting; Medium entropy alloy; Hierarchical microstructure; Synchrotron X-ray diffraction; Nano-twinning

摘要：The CrCoNi medium entropy alloy (MEA) is a technologically intriguing material showing superior cryogenic mechanical properties. In this work, we fabricated near full-dense hierarchical CrCoNi MEA via selective laser melting (SLM) and achieved superior yield strength of 860 MPa at 77K that surpasses that of conventionally fabricated counterparts, in addition to reasonable ductility. The strength and ductility increase as temperature drops, reaching a 1340 MPa ultimate tensile strength and a 47% elongation at 77K. EBSD, TEM, and in-situ synchrotron X-ray diffraction (SXRD) tensile tests disclose that the high strength stems from the hierarchical microstructure composed of high-density dislocations-formed cellular structures and low-angle grain boundaries (LAGB) within the complex heterogeneous columnar grains, and further validated by theoretical calculation. Insitu SXRD tensile tests and post-deformation TEM and EBSD reveal that nano-twinning response in the SLM-built CrCoNi MEA is suppressed by both high-density LAGB and near 100 growth texture. The results demonstrate that SLM is a viable technique for fabricating dense hierarchical CrCoNi MEA and suggest a design strategy to improve mechanical properties further.