Effects of cooling rate on microstructure and microhardness of directionally solidified Galvalume alloy  

作　　者：Ji-peng Li De-gao Qiao Jian Li Xiao-yang Luo Peng Peng Xian-tao Yan Xu-dong Zhang 

机构地区：[1]Gansu Jiu Steel Group Hongxing Iron and Steel Co.,Ltd.,Jiayuguan 735111,Gansu,China [2]School of Materials and Energy,Lanzhou University,Lanzhou 730000,China

出　　处：《China Foundry》2024年第3期213-220,共8页中国铸造（英文版）

基　　金：supported by the Key Science and Technology Projects of Gansu Province(Grant No.22ZD6GB019);Gansu Key Research and Development Project(Grant No.23YFGA0003);Gansu Provincial Joint Research Fund(Grant No.23JRRC0004);Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2022-ey15);the State Key Laboratory of Solidification Processing in NPU(Grant No.SKLSP202204).

摘　　要：The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich phase.In addition,the primary Al dendrites show significant refinement with an increase in the withdrawal speed.The relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 HV.This is a combined effect of grain refinement and second-phase strengthening.

关 键 词：Galvalume alloy directional solidification microstructure length scale MICROHARDNESS 

分 类 号：TG146.21[一般工业技术—材料科学与工程]