(1. 湖南科技大學 高溫耐磨材料及制備技術(shù)湖南省國防科技重點實驗室，湘潭 411201；
2. 湖南工學院 汽車零部件技術(shù)研究院，衡陽 421002)
摘 要: 對鑄態(tài)AZ31鎂合金進行溫度350~450 ℃、平均應(yīng)變速率為2.26~8.3 s-1的中高應(yīng)變速率軋制，研究軋制后鎂板的邊裂和組織性能。研究結(jié)果表明：隨著平均應(yīng)變速率增加，軋制邊裂得到改善；軋后鎂板室溫拉伸斷裂方式具有韌-脆性斷裂向韌性斷裂轉(zhuǎn)變的趨勢，在拉伸斷口中觀察到拉長形孔洞和夾著韌窩的層狀結(jié)構(gòu)；鎂合金抗拉強度受細晶強化和孿晶強化的共同作用，建立了考慮細晶強化和孿晶強化疊加的本構(gòu)關(guān)系。
關(guān)鍵字: AZ31鎂合金；中高應(yīng)變速率軋制；邊裂；組織；斷裂方式
（1. Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province, Hunan University of Science and Technology, Xiangtan 411201, China;
2. Research Institute of Automobile Parts Technology, Hunan Institute of Technology, Hengyang 421002, China）
Abstract:The medium-high strain rate rolling was carried out on as-casting AZ31 magnesium alloys over the temperature ranges from 350 to 450 ℃ with average strain rates of 2.26-8.3 s-1. The edge cracks, microstructures and mechanical properties were investigated. The results show that the edge crack is improved and the fracture mechanism of magnesium rolling sheet tends to transform from ductile-brittle fracture to ductile fracture with increasing average strain rate. The tensile fracture displays elongated holes and laminar structure with dimples. The tensile strength of magnesium alloy is affected by fine-grain strengthening and twins strengthening. A constitutive relation considering the fine-grain strengthening and twins strengthening was built.
Key words: AZ31 magnesium alloy; medium-high strain rate rolling; edge crack; microstructure; fracture mechanism
