Precipitate Characteristics and Mechanical Performance of Cast Mg–6RE–1Zn–xCa–0.3Zr(x=0 and 0.4 wt%) Alloys  

作　　者：Zijian Yu Xi Xu Baotian Du Kang Shi Ke Liu Shubo Li Xiuzhu Han Tao Xiao Wenbo Du 

机构地区：[1]College of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China [2]Beijing Institute of Spacecraft System Engineering,Beijing 100094,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2022年第4期596-608,共13页金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.51801048);the Beijing Natural Science Foundation(No.2202004);the Basic Research Fund for Newly Enrolled Teachers。

摘　　要：In this study,the Mg–4Y–1Gd–1Nd–xCa–1Zn–0.3Zr(x=0 and 0.4 wt%)cast alloys with low rare earth concentration were prepared in different routes of heat treatments,and their microstructures and mechanical properties were investigated.The Mg–4Y–1Gd–1Nd–1Zn–0.4Ca–0.3Zr cast alloy with ultimate tensile strength(UTS)of 264±7.8 MPa,tensile yield strength(TYS)of 153±1.2 MPa and elongation to failure(EL)of 17.2±1.2% was successfully developed by appropriate heat treatment.The improved mechanical performance was attributed to the combined strengthening effects of fine grains,Mg24RE5,β′,β_(1),γ′and LPSO phases.In the heat treatment process,cooling method of T4 treatment affected the microstructure,which consequently determined the mechanical properties air cooling,rather than water cooling,gave rise to the formation of γ′phase in the alloy without Ca addition.However,Ca addition facilitated the formation of γ′phase,and the γ′phase precipitated in the alloy after T4 treatment either by water cooling or by air cooling,but the air cooling increased the number density of γ′phase in comparison to the water cooling.Although the γ′phase strengthened the studied alloys,the formation of γ′phase inhibited the precipitatition of β′and β_(1) phases in the following T6 treatment,and consequently reduced the strengthening effect ofβ′andβ_(1) phases.The results showed that the mechanical performance of the studied alloys was largely determined by the precipitation of γ′phase,which was regulated by the Ca addition and the cooling method of T4 treatment.

关 键 词：Magnesium alloy Microstructure Mechanical properties Rare earth Heat treatment 

分 类 号：TG146.22[一般工业技术—材料科学与工程]