细晶AZ31镁合金高温压缩变形行为研究

High Temperature Deformation Behavior of Fine-Grained AZ31 Magnesium Alloy

通过Gleeble-1500试验机对坯料预先经过晶粒细化处理的AZ31镁合金圆柱体试样进行单向热压缩试验,压缩温度为300～450℃,应变速率.ε为0.01s-1,0.1s-1,1.0s-1,根据试样结果分析计算了本构方程中的各参数,获得了完整的镁合金高温本构方程,进一步分析了压缩试样的显微组织。结果表明:在本试验条件下,AZ31镁合金的热变形应力指数n为6.24,热变形激活能为177.2kJ/mol。压缩试样心部组织变形程度明显高于边缘;随着温度的升高,心部压缩组织发生明显的再结晶,新晶粒在晶界处形核并长大。

Unidirectional hot compressive tests of AZ31 magnesium alloy after grain refinement were performed by Gleeble-1500 machine at strain rates changed among 0.01 -1 s^ -1 and deformation temperature varied among 300 - 450℃. Each parameter of the constitutive equation was gained by analyzing and calculating the results of samples, and a complete constitutive equation of AZ31 magnesium alloy for high temperature was fabricated, furthermore, the mierostruetures of compressive samples were studied. The results show that the hot deformation activation energy Q is 177. 181 kJ/mol and the stress exponent n is 6.24. Compared with the edge of the compressive samples, the center has more intense degeneration. With the temperature increasing, obvious recrystallization is observed in the compressive organization. The new grain forms toward the crystal boundary and then grows up.