论文部分内容阅读
采用Gleeble-3500热模拟试验机,对铸态AZ80+0.4%Ce镁合金在变形温度为300~420℃、应变速率为0.0005~0.5 s-1条件下进行热压缩试验,获得其真应力-应变曲线。用ZEISS金相显微镜观察不同变形条件下的显微组织,并根据实验结果建立热加工图。结果表明:随变形温度升高流变应力值减小,动态再结晶明显,晶粒细化,β-Mg17Al12相充分溶于基体中,另外呈针状分布的Al4Ce相破碎;随应变速率增大流变应力值增大,变形时间变短,动态再结晶不明显,晶粒粗大,β-Mg17Al12相溶解不充分。AZ80+0.4%Ce镁合金的变形安全区为变形温度340~390℃,应变速率0.5×10-3~0.5×10-2s-1,该区域动态再结晶明显,晶粒呈等轴形貌,细小且均匀;变形失稳区包括两个区域:在低温高应变速率区域,局部流变带的产生引起开裂;在高温高应变速率区域,β-Mg17Al12相集中的地方产生孔洞状裂纹。
Using Gleeble-3500 thermal simulation testing machine, the hot compression test was carried out on the as-cast AZ80 + 0.4% Ce magnesium alloy under the condition of deformation temperature of 300-420 ℃ and strain rate of 0.0005-0.5 s-1, and the true stress-strain curve. ZEISS metallographic microscope was used to observe the microstructure under different deformation conditions, and the thermal processing diagram was established according to the experimental results. The results show that the rheological stress decreases with the increase of deformation temperature, the dynamic recrystallization is obvious and the grains are refined. The β-Mg17Al12 phase is fully dissolved in the matrix, while the Al4Ce phase with acicular disintegration breaks down. With the increase of strain rate The rheological stress increases, the deformation time becomes shorter, the dynamic recrystallization is not obvious, the crystal grains are coarse, and the β-Mg17Al12 phase is not dissolved sufficiently. The deformation safety zone of AZ80 + 0.4% Ce magnesium alloy has a deformation temperature of 340-390 ℃ and a strain rate of 0.5 × 10-3-0.5 × 10-2s-1. The dynamic recrystallization of AZ80 + 0.4% Which is small and uniform. The zone of deformation and destabilization consists of two zones. In the high temperature and high strain rate region, the local rheological zone leads to cracking. In the high temperature and high strain rate zone, holes are formed in the β-Mg17Al12 phase.