A new insight into LPSO phase transformation and mechanical properties uniformity of large-scale Mg-Gd-Y-Zn-Zr alloy prepared by multi-pass friction stir processing  

作　　者：Xiaohu Guan Wen Wang Ting Zhang Pai Peng Qiang Liu Peng Han Ke Qiao Jun Cai Liqiang Wang Kuaishe Wang 

机构地区：[1]School of Metallurgical Engineering,National and Local Joint Engineering Research Center for Functional Materials Processing,Xi’an University of Architecture and Technology,No.13 Yanta Road,Xi’an,Shaanxi 710055,China [2]Xi’an Rare Metal Materials Institute Co.Ltd,Xi’an 710016,China [3]State Key Laboratory of Metal Matrix Composites,School of Material Science and Engineering,Shanghai Jiao Tong University,No.800 Dongchuan Road,Shanghai 200240,China

出　　处：《Journal of Magnesium and Alloys》2024年第5期2041-2056,共16页镁合金学报（英文）

基　　金：supported by the National Key Research and Development Program of China(2021YFB3501002);State Key Program of National Natural Science Foundation of China(5203405);National Natural Science Foundation of China(51974220,52104383);National Key Research and Development Program of China(2021YFB3700902);Key Research and Development Program of Shaanxi Province(2020ZDLGY13-06,2017ZDXM-GY-037);Shaanxi Province National Science Fund for Distinguished Young Scholars(2022JC-24)。

摘　　要：A large-scale fine-grained Mg-Gd-Y-Zn-Zr alloy plate with high strength and ductility was successfully prepared by multi-pass friction stir processing(MFSP)technology in this work.The structure of grains and long period stacking ordered(LPSO)phase were characterized,and the mechanical properties uniformity was investigated.Moreover,a quantitative relationship between the microstructure and tensile yield strength was established.The results showed that the grains in the processed zone(PZ)and interfacial zone(IZ)were refined from 50μm to 3μm and 4μm,respectively,and numerous original LPSO phases were broken.In IZ,some block-shaped 18R LPSO phases were transformed into needle-like 14H LPSO phases due to stacking faults and the short-range diffusion of solute atoms.The severe shear deformation in the form of kinetic energy caused profuse stacking fault to be generated and move rapidly,greatly increasing the transformation rate of LPSO phase.After MFSP,the ultimate tensile strength,yield strength and elongation to failure of the large-scale plate were 367 MPa,305 MPa and 18.0% respectively.Grain refinement and LPSO phase strengthening were the major strengthening mechanisms for the MFSP sample.In particularly,the strength of IZ was comparable to that of PZ because the strength contribution of the 14H LPSO phase offsets the lack of grain refinement strengthening in IZ.This result opposes the widely accepted notion that IZ is a weak region in MFSP-prepared large-scale fine-grained plate.

关 键 词：Friction stir processing MULTI-PASS Mg-Gd-Y-Zn-Zr alloy LPSO phase transformation Mechanical properties 

分 类 号：TG146.22[一般工业技术—材料科学与工程]