Hardness-thermal stability synergy in nanograined Ni and Ni alloys:Superposition of nanotwin and low-energy columnar boundary  

作　　者：F.H.Duan Y.Lin Q.Li J.H.Luan J.Lu J.Pan Y.Li 

机构地区：[1]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [2]Laboratory of Nanomaterials&Nanomechanics,Department of Mechanical Engineering,City University of Hong Kong,Hong Kong,China [3]State Key Laboratory of Material Processing and Die&Mould Technology and School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China [4]Department of Materials Science and Engineering,City University of Hong Kong,Hong Kong,China [5]Centre for Advanced Structural Materials,Greater Bay Joint Division,Shenyang National Laboratory for Materials Science,City University of Hong Kong Shenzhen Research Institute,Shenzhen 518057,China [6]City U-Shenzhen Futian Research Institute,Shenzhen 518045,China

出　　处：《Journal of Materials Science & Technology》2023年第6期123-131,共9页材料科学技术（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.52022100,52001075,and 52101162);the Shenyang National Laboratory for Materials Science(No.E01SL102);J.Pan is also grateful for support from the Youth In-novation Promotion Association of the Chinese Academy of Sci-ences(No.2020194);Y.Li acknowledges financial support from the Shenyang National Laboratory for Materials Science.J.Lu gratefully acknowledges the support of the National Key R&D Program of China(No.2017YFA0204403);the Major Program of the National Natural Science Foundation of China(NSFC,No.51590892);the Hong Kong Collaborative Research Fund(CRF)Scheme(C4026-17W);Theme-Based Research Scheme(Ref.T13-402/17-N);Gen-eral Research Fund(GRF)Scheme(CityU 11247516,CityU 11209918,CityU 11216219);Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park Project(No.HZQB-KCZYB-2020030).Atom probe tomography research was conducted at the Inter-University 3D Atom Probe Tomography Unit of the City University of Hong Kong,which is supported by the CityU grant 9360161.

摘　　要：Refining grains into nanoscale can significantly strengthen and harden metallic materials;however,nanograined metals generally exhibit low thermal stability,hindering their practical applications.In this work,we exploit the superposition of the contribution of nanotwins,low-angle grain boundaries,and microalloying to tailor superior combinations of high hardness and good thermal stability in Ni and Ni alloys.For the nanotwinned Ni having a twin thickness of∼2.9 nm and grain size of 28 nm,it exhibits a hardness over 8.0 GPa and an onset coarsening temperature of 623 K,both of which are well above those of nanograined Ni.Re/Mo microalloying can further improve the onset coarsening temperature to 773 K without comprising hardness.Our analyses reveal that high hardness is achieved via strengthen-ing offered by extremely fine nanotwins.Meanwhile,the superior thermal stability is mainly ascribed to the low driving force for grain growth induced by the low-angle columnar boundary architecture and to the additional pinning effect on the migration of twin/columnar boundaries provided by minor Re/Mo solutes.The present work not only reveals a family of nanotwinned metals possessing the combination of ultra-high hardness and high thermal stability but also provides a strategy for tailoring properties of metallic materials by pairing low-angle grain boundaries and twin boundaries.

关 键 词：Nanotwin Thermal stability HARDNESS Low-angle grain boundary MICROALLOYING 

分 类 号：TG146.15[一般工业技术—材料科学与工程] TB383.1[金属学及工艺—金属材料]