镁合金双道次热变形静态软化及残余应变研究

The Study on Static Softening and Residual Strain in the Two-stage Thermal Deformation of Magnesium alloy

摘要:

在变形温度250~450℃、变形速率0.005~5s-1和道次间隔时间15~240s下对AZ31B镁合金进行了双道次等温压缩试验,研究不同变形工艺条件对AZ31B镁合金道次间软化规律的影响,建立了AZ31B镁合金道次间软化率预测模型。根据轧制残余应变产生的原因提出了多道次轧制过程中残余应变率的计算方法。研究结果表明：随着变形温度和变形速率的提高,材料的静态软化率逐渐增大,道次间间隔时间越长材料软化程度越大。建立的道次间静态软化率计算模型能够很好地表征AZ31B镁合金道次间软化规律,平均相对误差为12.58%。进一步对残余应变率的精确计算能够为AZ31B镁合金多道次轧制过程中轧制力的求解提供理论支持。

Abstract:

The Static softening behavior in the two-stage isothermal compression of AZ31B magnesium alloy is investigated at the deformation temperatures ranging from 250℃ to 450℃, strain rates ranging from 0.005s-1 to 1s-1 and the inter-pass times ranging from 15s to 240s after the first stage isothermal compression. The prediction model of softening rate was established. According to the essence of rolling residual strain rate, the calculation method of residual strain rate in multi pass rolling process was proposed. The results show that the static softening fraction increases with the increasing of deformation temperature, strain rate and the inter-pass times. The softening rate calculation model can be used to characterize the softening rule of AZ31B magnesium alloy, the average relative error is 12.58%.The calculation model of residual strain rate can provide technical support for solving the deformation resistance of AZ31B magnesium alloy during multi pass deformation process.