Ultra-strong and thermally stable nanocrystalline CrCoNi alloy

作     者：Peng Gao Shuo Sun Heng Li Ranming Niu Shuang Han Hongxiang Zong Hao Wang Jianshe Lian Xiaozhou Liao Peng Gao;Shuo Sun;Heng Li;Ranming Niu;Shuang Han;Hongxiang Zong;Hao Wang;Jianshe Lian;Xiaozhou Liao

作者机构：School of AerospaceMechanical&Mechatronic EngineeringThe University of SydneySydneyNSW 2006Australia Key Laboratory of Automobile MaterialsMinistry of EducationCollege of Materials Science and EngineeringJilin UniversityChangchun 130025China State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2022年第106卷第11期

页      面：1-9页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the Australian Government under the NCRIS program supported by the National Natural Science Foundation of China (No.51601067) the Science and Technology Development Program of Jilin Province (No.20160520007JH) Hongxiang Zong was supported by the National Natural Science Foundation of China (No.51871177) Xiaozhou Liao is supported by the Australian Research Council Discovery Project DP190102243 

主　　题：Medium entropy alloy CrCoNi Nanocrystalline In-situ microscopy Mechanical properties Thermal stability 

摘      要：Grain refinement to the nanocrystalline regime is the most effective way to strengthen materials but this often deteriorates the grain-size thermal stability and plasticity. Here we manufactured a nanocrystalline face centred cubic Cr Co Ni medium entropy alloy with columnar grains via magnetron sputtering. Compression of CrCoNi pillars with diameters of ~1 μm revealed a record high yield strength of ~5 GPa for pillars with face centred cubic structures and engineering plastic strain of 30%. The alloy possessed an outstanding grain-size thermal stability even at 1073 K. Both nanocrystalline grain size and a high density of nanotwins/stacking faults are critical to the exceptional yield strength. Deformation twinning, grains refinement during deformation, grain boundary sliding and random grain orientation all contribute to the large plasticity. The outstanding thermal stability is attributed to the sluggish diffusion effect and the low energy of twin boundaries.