Effects of heat treatment on mechanical properties of an extruded Mg-4.3Gd-3.2Y-1.2Zn-0.5Zr alloy and establishment of its Hall–Petch relation

作     者：Lei Liu Xiaojie Zhou Shilun Yu Jian Zhang Xianzheng Lu Xin Shu Zaijun Su Lei Liu;Xiaojie Zhou;Shilun Yu;Jian Zhang;Xianzheng Lu;Xin Shu;Zaijun Su

作者机构：Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical EquipmentChangsha University of Science and TechnologyChangsha 410114China Hunan Xiangtou Goldsky Titanium Metal Co.Ltd.Changsha 410205China Hunan Aerospace Tianlu Advanced Material Testing Co.LtdChangsha 410600China School of Mechanical EngineeringHunan University of TechnologyZhuzhou 412007China 

出 版 物：《Journal of Magnesium and Alloys》 (镁合金学报（英文）)

年 卷 期：2022年第10卷第2期

页      面：539-551页

核心收录：

学科分类：08[工学] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0802[工学-机械工程] 0703[理学-化学] 080201[工学-机械制造及其自动化] 0801[工学-力学（可授工学、理学学位）] 

基　　金：the National Natural Science Foundation of China(Nos.51904036 and 51874049) the Hunan Provincial Natural Science Foundation of China(Nos.2020JJ5600 and 2018JJ2365) the Hunan Education Department Outstanding Youth Project of China(No.17B069) the Scientific Research Project of Hunan Education Department(No.20C0088). 

主　　题：Magnesium alloys Heat treatment Hall–Petch Mechanical properties Strengthening mechanism 

摘      要：The effects of T4,T5,and T6 treatment on the microstructure and mechanical properties of the extruded Mg-4.3Gd-3.2Y-1.2Zn-0.5Zr(wt.%)alloy with a relatively low RE content(7.5 wt.%)were investigated.T4 treatment at 450–500°C induces a gradual grain growth ofα-Mg but an obvious transition of texture component from⊥ED to∥ED.Interdendritic LPSO phases are highly stable against annealing while intragranular ones experience dissolution and re-precipitation.After peak-ageing at 200°C,the elongation of as-extruded and T4 samples is just slightly reduced or even increased due to the weak ageing hardening response.T5 sample exhibits an attractive combination of strength and ductility,with a tensile yield strength(TYS)of 303 MPa and elongation of 20.0%.The Hall–Petch relation for the alloys with or without ageing treatment has been estimated.Grain boundary strengthening rather than precipitation strengthening has the dominant contribution to TYS,and a modified equation is developed to predict grain boundary strengthening values for Mg-Gd-Y-Zn-Zr alloys which contain different Schmid factors for basal slip.