新型Al-Mg-Si-RE合金的热变形行为

设计制备了4种不同Mg/Si比并添加稀土元素Ce、Er、Zr和B的新型Al-Mg-Si合金,并研究了其显微组织与导电率及抗拉强度。然后以一种优化成分的Al-Mg-Si-RE合金为研究对象,通过 Gleeble-3500热模拟机进行热压缩试验,研究了变形温度为300~450 ℃,应变速率为0.001~1 s^-1时该新型合金的热变形行为。通过试验数据构建该合金的本构方程和热加工图,通过光学显微镜研究显微组织的演变。结果表明,当Mg/Si比为1.4时,该合金具有优异的性能,该合金流变应力随着变形温度的升高而降低,随应变速率的增大而增大。计算得到该合金的热变形激活能为176.188 kJ/mol,所得本构方程对该合金的流变行为具有指导作用。由热加工图可知,该合金适宜在变形温度为300~320 ℃,应变速率为0.001~0.015 s^-1或变形温度为430~450 ℃,应变速率为0.001 s^-1或1 s^-1附近的条件下进行热加工。

Thermal deformation behavior of novel Al-Mg-Si-RE alloys

Four novel Al-Mg-Si alloys with different Mg/Si ratios and additions of Zr and B, and rare earth elements (Ce and Er) were designed and prepared, and the microstructure, electrical conductivity and tensile strength were studied. Then taking the Al-Mg-Si-RE alloy with a optimum chemical composition as the research object, the thermal compression test was carried out by Gleeble-3500 thermal simulator, and the thermal deformation behavior of the alloy was studied with the deformation temperature of 300-450 ℃ and the strain rate of 0.001-1 s^-1. The constitutive equation and hot processing map of the alloy were constructed through experimental data, and the evolution of microstructure was studied by optical microscope. The results show that when the Mg/Si ratio is 1.4, the alloy has excellent properties. The flow stress of the alloy decreases with the increase of deformation temperature and the decrease of the strain rate. The thermal deformation activation energy of the alloy is calculated to be 176.188 kJ/mol, the constitutive equation obtained has a guiding effect on the flow behavior of the alloy. The hot processing map shows that the suitable processing regimes are deformation temperature of 300-320 ℃, strain rate of 0.001-0.015 s^-1, and deformation temperature of 430-450 ℃, strain rate near 0.001 s^-1or 1 s^-1.