Lamellar aspect-ratio and thickness-dependent strength-ductility synergy in pure nickel during in-situ micro-tensile loading  

作　　者：Zi-Meng Wang Yun-Fei Jia Kai-Shang Li Yong Zhang Jia-Dong Cai Xian-Cheng Zhang Hiroyuki Hirakata Shan-Tung Tu 

机构地区：[1]Key Laboratory of Pressure Systems and Safety,Ministry of Education,School of Mechanical and Power Engineering,East China University of Science and Technology,Shanghai 200237,China [2]Department of Mechanical Engineering and Science,Kyoto University,Kyoto daigaku-katsura,Nishikyo-ku,Kyoto 615-8540,Japan

出　　处：《Journal of Materials Science & Technology》2023年第26期89-97,共9页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foun-dation of China(grant Nos.52222505,51975211,and 51725503);Shanghai Rising-Star Program(grant No.20QA1402500);Foun-dation Strengthening Plan Technology Field Fund Project(grant No.2019-JCJQ-JJ-454).

摘　　要：In order to overcome the trade-offbetween strength and ductility in traditional metallic materials,the gradient lamellar structure was fabricated through an ultrasound-aided deep rolling technique in pure Ni with high stacking fault energy after heat treatment.The gradient lamellar Ni was successively di-vided into three regions.In-situ micro-tensile tests were performed in different regions to reveal the corresponding microscopic mechanical behaviors.Microscopic characterization techniques were adopted to explore the effects of microstructural parameters and defects on mechanical properties.This work demonstrates that the micro-tensile sample with small lamellar thickness and large aspect ratio possesses excellent strength and ductility when the loading direction is parallel to the long side of lamellar grain boundaries.The finding is helpful to the design of metallic material microstructure with superior com-prehensive properties.On one hand,the reason for high strength is that the strength increases with the decrease of lamellar thickness according to the Hall-Petch effect.Besides,initial dislocation density also participates in the strengthening mechanism.On the other hand,the deformation mechanisms include dislocation slip,grain rotation,and the effects of grain boundaries on dislocations,jointly contributing to good ductility.

关 键 词：LAMELLA In-situ micro-tensile test Strength-ductility synergy Aspect ratio Grain rotation 

分 类 号：TG146.21[一般工业技术—材料科学与工程]