中文摘要：

以变形条件对AZ80镁合金材料临界损伤因子的影响为主要研究目标,确立了物理试验与数值模拟仿真相互佐证寻求临界损伤因子的基本思路。完成不同温度和应变速率条件下多组试样的热物理模拟压缩试验,利用采集到的真应力-真应变数据作为-数值模拟的基本材料参数完成物理试验的仿真再现,发现最大损伤值总是出现在镦粗鼓的最外缘部位,损伤软化现象对应变速率较为敏感。提出损伤敏感率的概念并完成该指标的计算,对损伤敏感率曲线进行局部线性回归拟合,从而确定了损伤敏感率为0,即裂纹产生的时刻,并将该时刻的最大损伤因子作为临界损伤因子。计算出AZ80镁合金在不同温度及应变速率下的临界损伤因子分布规律,发现AZ80镁合金的临界损伤因子不是一个常数,而是一个在0.0218～0.378范围内变化的变量,其对应变速率变化较温度变化更为敏感。

英文摘要：

The main research objective is to analyze the influence of deformation conditions on the critical damage factor of AZ80 magnesium alloy.A basic research approach that physical experiments and numerical simulation provide mutual support for the critical damage factor was established.As several series of billet samples had been compressed on heat physical simulation machine under different deformation temperatures and strain rates,the true stress-strain data collected resulted the performance of simulations.Simulation results show that the maximum damage value appears on the outer edge of upsetting drum,and damage softening behavior is more sensitive to strain rate.A concept of damage sensitive rate was brought forth and its values were computed.The intersection of line fitted and horizontal axis was obtained as the fracture step and its relative maximum damage value was as a critical damage factor.The critical damage value distribution computed shows that it is not a constant but a change with a range 0.0218-0.378,and it is more sensitive on strain rate than temperature.