用Gleeble-1500D型热模拟试验机对AZ31镁合金在变形温度为473~723 K,应变速率为0.001~1 s-1下的热变形行为进行了试验研究;用双曲正弦关系式描述了该合金在热变形过程中的稳态流变应力;根据合金动态模型,计算并分析了该合金的加工图.结果表明:利用加工图可确定出该合金热变形的流变失稳区,并且得到试验条件下热变形的最佳工艺参数,即变形温度为473~523 K,应变速率为0.01 s-1左右;当变形温度为623~673 K、应变速率为0.001~0.006 s-1时可进行超塑性加工;当变形温度高于673 K后可在较宽的应变速率范围进行热加工.

The hot deformation behavior of AZ31 magnesium alloy was investigated by thermo-compression tests with Gleeble-1500D thermal simulator.The tests were performed in the temperature range from 473 to 723 K and at strain rates from 0.001 to 1 s-1.The steady flow stress was described by the hyperbolic sine constitutive equation.The processing maps were drawn and analyzed according to the dynamic material model.The results show that the instability zones of flow behavior could also be recognized by the maps.The optimal processing parameters of hot deformation under the test condition was able to be attained by the maps as follow: hot deformation temperature of 473-523 K and strain rate around 0.01 s-1.The superplastic forming could be performed when the temperature was 623-673 K and strain rate was about 0.001-0.006 s-1.The range of strain rate could be wider when the deformation temperature was higher than 673 K.