Properties and microstructure of copper–titanium alloys with magnesium additions  

作　　者：Lue Huang Li-Jun Peng Jiang Li Xu-Jun Mi Gang Zhao Guo-Jie Huang Hao-Feng Xie Yi-Cheng Cao Wen-Jing Zhang Zhen Yang 

机构地区：[1]State Key Laboratory of Nonferrous Metals and Processes,GRINM Group Co.,Ltd.,Beijing 100088,China [2]GRIMAT Engineering Institute Co.,Ltd,Bejing 101407,China [3]School of Materials Science and Engineering,Northeastern University,Shenyang110000,China [4]General Research Institute for Nonferrous Metals,Beijing 100088,China [5]China Academy of Space Technology,Beijing 100094,China [6]China Nonferrous Metals Mining Group(Tianjin)Co.Ltd,Tianjin 3001ll,China

出　　处：《Rare Metals》2024年第5期2290-2299,共10页稀有金属（英文版）

基　　金：financially supported by the Technological Innovation 2025&Major Special Project of Ningbo(Nos.2021Z084 and 2020Z039)。

摘　　要：The volume fractions and morphology of precipitates in precipitation-strengthened Cu-Ti alloys,which precipitate mainly as continuous and discontinuous precipitates,are important for the application of the alloy.This study employed hardness and electrical conductivity tests transmission electron microscopy(TEM),atom probe tomography(APT),and first-principles calculations to demonstrate that the addition of Mg is effective for accelerating nanosized continuousβ'-Cu_(4)Ti precipitation as well as for suppressing the precipitation of coarse lamellar discontinuousβ-Cu_(4)Ti precipitates along the grain boundaries,resulting in Cu-Ti alloys with high yield strength and good electrical conductivity.The results showed that the continuous precipitation ofβ'-Cu_(4)Ti was accelerated by the Mg additions,which reduced the supersaturation of the matrix,thereby reducing the chemical driving force for the discontinuous precipitates.On the other hand,Mg additions increased the mismatch between the discontinuousβ-Cu_(4)Ti precipitates and matrix decreased the nucleation rate of the discontinuous precipitates,and increased the spacing of the discontinuous precipitation layer,resulting in a lower growth rate of the discontinuous precipitates.Therefore,the addition of Mg to Cu-Ti alloys enhances the strength and improves the resistance to over-ageing.

关 键 词：Cu-Ti-Mg alloy Precipitation hardening Discontinuous precipitation Continuous precipitation Microstructure formation mechanism 

分 类 号：TG146.11[一般工业技术—材料科学与工程]