Mg-6.3Zn-0.7Zr-0.9Y-0.3Nd合金高温变形行为及热加工图

摘要

The hot deformation behavior of Mg-6.3Zn-0.7Zr-0.9Y-0.3Nd alloys was investigated by hot compressive tests on Gleeble-1500 thermal simulation test machine at 623-773 K and at the strain rates of 0.001-1 s-1. The hot processing map was established based on the dynamic material model (DMM). The results show that the efficiency of power dissipation is above 30% when deformed at interval 1 (7=643-703 K, ε =0.001-0.1 s-1) and interval 2 (T=703-773 K, ε=0.005—0.1 s-1). The typic dynamic recrystallization structure appears in these two areas which are the optional processing parameters of hot deformation. Two instability zones of flow behavior are established as follows: hot temperature of 623-643 K, strain rate of 0.1-1 s-1 and hot temperature of 703-760 K, strain rate of 0.3-1 s-1, respectively.%采用Gleeble-1500热模拟试验机进行热压缩试验,研究Mg-6.3Zn-0.7Zr-0.9Y-0.3Nd合金在变形温度T=623～773K、应变速率ε=0.001～1 S-1时的变形行为,并根据动态材料模型(DMM)建立该合金的热加工图.研究结果表明:该合金在区间1(T=643～703K,ε=0.001～0.1 S-1)以及区间2(T=703～773K,ε=0.005～0.1 s-1)变形时,功率耗散效率均大于30％；区域内合金具有典型的动态再结晶组织,因而两区域对应的变形工艺为该合金的最佳热变形工艺；合金热变形的2个流变失稳区分别为:T=623～643 K,ε=0.1～1 s-1；T=703～760 K,ε=0.3～1 S-1.