AZ91D镁合金高温压缩变形行为

High temperature compression deformation behaviors of AZ91D alloy

针对AZ91D镁合金,采用Gleeble1500D热模拟实验机对原始铸态试样在不同温度和应变速率下的高温压缩变形行为进行了实验研究。结果表明,AZ91D镁合金在压缩温度为200℃时,随着应变速率增大,应力升高加快;压缩温度为300-400℃、应变速率为0.001-1 s^-1时,材料呈现出稳态流变的特性;当应变速率提高到5 s^-1时,未出现稳态流变现象。建立了AZ91D镁合金低、高温压缩的变形力学模型,其结果可为镁合金的塑性成形工艺的制订提供理论依据。

The high temperature compression test to the original casting sample of AZ91D magnesium alloy was carried out on the Gleeble1500 thermal simulation testing machine under the different temperatures and the strain rates. The results show that when compression temperature is 200 ℃, the stress increases more rapidly with the strain rate get ting greater; when compression temperature is 300 - 400℃ and the strain rate is 0. 001 - 1 s^-1 , the material shows the steady flowing behavior and there is no obvious peak stress; even though strain is greater than 0.6, there is no crack, and strain rate reaches to 5 s ^-1, there is no sign of steady flowing behavior. Based upon the test results, the mathematics models of deformation on low and high temperatures were established, and its result might provide a more scientific basis for plastic forming of AZ91D magnesium alloy.