An insight into Mg alloying effects on Cu thin films:microstructural evolution and mechanical behavior  

作　　者：G.Y.Li L.F.Cao J.Y.Zhang X.G.Li Y.Q.Wang K.Wu G.Liu J.Sun 

机构地区：[1]State Key Laboratory for Mechanical Behavior of Materials,Xi'an Jiaotong University,Xi'an,710049,China [2]International Joint Laboratory for Light Alloys(Ministry of Education),College of Materials Science and Engineering,Chongqing University,Chongqing,400044,China [3]Electron Microscopy Center of Chongqing University,Chongqing University,Chongqing,400044,China

出　　处：《Journal of Materials Science & Technology》2020年第22期101-112,共12页材料科学技术（英文版）

基　　金：financially supported by the National Key Research and Development Program of China (No. 2017YFA0700701);the National Natural Science Foundation of China (Nos. 51722104, 51625103, 51790482 and 51761135031);the “111 Project 2.0 of China” (No. BP2018008);the Fok Ying-Tong Education Foundation (No. 161096);the Fundamental Research Funds for the Central Universities for part of the financial support;the financial support by the Venture & Innovation Support Program for Chongqing Overseas Returnees (cx2018002);the National Defense Basic Scientific Research Program;the Fundamental Research Funds for the Central Universities (2020CDJDCL001)。

摘　　要：How to design ultra-strong,light-weight Cu alloys is a long-term pursuit in materials community,which is technically superior and cost-effective for their promising energy-saving applications.In this work,we prepared Cu-Mg alloyed thin films to study light element Mg alloying effects on the microstructure,hardness and strain rate sensitivity(SRS) of nanocrystalline Cu thin films.In the studied Mg concentrationrange spanning from 0 at.% to 16.8 at.%,both the grain size and the twin spacing decrease monotonously with increasing Mg composition while Cu-2.8 at.% Mg sample has the highest twin fraction of ~75%.A combined strengthening model was employed to quantify the Mg concentration-dependent hardness of nanotwinned(NT) Cu-Mg thin films,in which the grain/twin boundary facilitates strengthening while the solute Mg atoms induce softening.Both the constant rate of loading tests and the nanoindentation creep tests uncover that compared with pure Cu samples,the NT Cu-Mg thin films manifest much lower SRS,particularly in the creep tests,owing to the activation of dynamic strain aging effects.

关 键 词：Cu-Mg thin films Microstructure evolution Creep tests Hardness Strain rate sensitivity 

分 类 号：TB383.2[一般工业技术—材料科学与工程]