Hot-deformation kinetics analysis and extrusion parameter optimization of a dilute rare-earth free magnesium alloy  

作　　者：Qinghang Wang Haowei Zhai Zhaoyang Jin Junjie He Qin Yang Wenjun Liu Yulong Li Daolun Chen 

机构地区：[1]School of Mechanical Engineering,Yangzhou University,No.196 West Huayang Road,Hangjiang,Yangzhou,225127,China [2]School of Materials and Energy,Yunnan University,Kunming,650599,China [3]Changan Auto Global R&D Center,Chongqing,401120,China [4]College of Materials Science and Engineering,Chongqing University of Technology,Chongqing,400054,China [5]Department of Mechanical and Industrial Engineering,Toronto Metropolitan University(formerly Ryerson University),Toronto,ON M5B 2K3,Canada

出　　处：《Journal of Magnesium and Alloys》2023年第9期3302-3322,共21页镁合金学报（英文）

基　　金：funded by the Postgraduate Research & Practice Innovation Program of Jiangsu Province (No.SJCX22_1720);the National Natural Science Foundation of China (No.51901204);the Chongqing Science and Technology Commission (Nos.cstc2020jcyj-msxmX0184 and cstc2019jscx-mbdxX0031);the University Innovation Research Group of Chongqing (No.CXQT20023)。

摘　　要：The fundamental research on thermo-mechanical conditions provides an experimental basis for high-performance Mg-Al-Ca-Mn alloys.However, there is a lack of systematical investigation for this series alloys on the hot-deformation kinetics and extrusion parameter optimization. Here, the flow behavior, constitutive model, dynamic recrystallization(DRX) kinetic model and processing map of a dilute rare-earth free Mg-1.3Al-0.4Ca-0.4Mn(AXM100, wt.%) alloy were studied under different hot-compressive conditions. In addition, the extrusion parameter optimization of this alloy was performed based on the hot-processing map. The results showed that the conventional Arrhenius-type strain-related constitutive model only worked well for the flow curves at high temperatures and low strain rates. In comparison, using the machine learning assisted model(support vector regression, SVR) could effectively improve the accuracy between the predicted and experimental values. The DRX kinetic model was established, and a typical necklace-shaped structure preferentially occurred at the original grain boundaries and the second phases. The DRX nucleation weakened the texture intensity, and the further growth caused the more scattered basal texture. The hot-processing maps at different strains were also measured and the optimal hot-processing range could be confirmed at the deformation temperatures of 600~723 K and the strain rates of 0.018~0.563 s^(-1). Based on the optimum hot-processing range, a suitable extrusion parameter was considered as 603 K and 0.1 mm/s and the as-extruded alloy in this parameter exhibited a good strength-ductility synergy(yield strength of ~ 232.1 MPa, ultimate strength of ~ 278.2 MPa and elongation-to-failure of ~ 20.1%). Finally, the strengthening-plasticizing mechanisms and the relationships between the DRXed grain size, yield strength and extrusion parameters were analyzed.

关 键 词：Mg-Al-Ca-Mn alloy Constitutive model Dynamic recrystallization kinetic model Extrusion parameter optimization Strengthening-plasticizing mechanisms 

分 类 号：TG379[金属学及工艺—金属压力加工]