Influence of heat treatment and hot extrusion on the microstructure and tensile properties of rare earth modified Mg-Zn based alloy

2nd International Conference on New Material and Chemical Industry

材料科学;化学工业

Sheng, L.Y.^1 ; Wang, B.J.^1 ; Du, B.N.^1 ; Lai, C.^1 ; Xi, T.F.^1

Shenzhen Institute, Peking University, southern 7 street, Hi-Tech Park, Shenzhen, China^1

关键词: Average grain size;    Eutectic structures;    Mg-zn-y-nd alloys;    Microstructure and mechanical properties;    Strengthening phase;    Strengthening phasis;    Ultrafine structure;    Zn-based alloys;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/292/1/012041/pdf
DOI  :  10.1088/1757-899X/292/1/012041

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

In the present paper, the Mg-Zn-Y-Nd alloy was prepared by casting, heat treatment and hot extrusion. The microstructure and mechanical properties of the alloys were tested by OM, SEM, TEM and tensile test. The results showed that the Mg3Zn2Y3phase is the main strengthening phase and forms the eutectic structure with α-Mg matrix in the as cast alloy. The strengthening phases semi-continuously connect and separate the α-Mg matrix into cell structure. The average grain size of the as cast alloy is about 60 μm. The heat treatment promotes the solid solution of the strengthening phase and precipitation of small particles inside grain.Compared with the as cast alloy, the heat treatment increases grain size a little and mechanical properties more than 30%. The hot extrusion refines the grain and strengthening phase, which increase the mechanical properties significantly. Moreover, the great deformation by the hot extrusion results in the ultrafine structure and abundant of crystal defects. The intersection of micro-twins lead to the special region with nanometer size.