Transactions of Materials and Heat Treatment

Title：Influence of large plastic forging passes on microstructure evolution of automotive Mg-13Gd-4Y-2Zn-0.5Zr alloy

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ClassificationCode：TG146.2

year,vol(issue):pagenumber：2022,47(4):62-67

Abstract：

Mg-13Gd-4Y-2Zn-0.5Zr alloy composed of LPSO phase was prepared by heat treatment method. Then, the transformation mechanism of torsion, twinning and dynamic recrystallization for the alloy during the forging process were analyzed, and the mechanical properties were optimized according to the change characteristics of microstructure. The results show that the microstructure of as-cast alloy consists of α-Mg matrix and reticulated eutectic compounds. The reticulated eutectic phase in as-cast alloy reaches the degree of remelting after homogenization treatment at 515 ℃ for 40 h, and the reticuleted eutectic phase transforms into alloy grains with uneven size distribution after annealing at 420 ℃ for 12 h. After one pass deformation, multiple variants are excited in some grains to cause twins, after two and three passes deformation, the alloy forms more twins composed of dynamic recrystallization grains, and after four passes deformation, the original strip twins in the grains all disappear. Therefore, by increasing the forging passes, the specimen obtains higher tensile strength and elongation. The research shows that quasi cleavage fracture occurs at the fracture, which is characterized by plasticity. In addition, after increasing the forging pass, a large number of dimples with smaller size are formed, and the mechanical strength of the alloy is obviously improved.

Funds：

河南省高等学校青年骨干教师培养计划项目（2017GGJS241）

作者简介：高飞（1983-），男，硕士，讲师 E-mail：gaofei122983@163.com

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