在试验基础上,采用有限元方法对AZ31镁合金在不同温度场中的挤压成形过程进行了数值模拟,详细分析了各种工艺参数对挤压中变形载荷、应变分布和温度场分布等的影响.结果表明：不同挤压条件下的挤压力模拟值与实测值相对误差小于10%,模拟结果与实际值比较接近;即使坯料和模具不加热,坯料挤出时的温度都达到了340 ℃以上;在坯料为常温、模具为300 ℃时的情况下,挤压力开始时较大,接近于常温变形时的挤压力,但随后挤压力下降;随摩擦因数增大挤压力有明显增加.坯料为常温时,随模具温度增加,挤压力开始变化不大,但当超过100 ℃后有明显下降.

Based on the experimental results,the extrusion process of magnesium alloys AZ31 under different temperature field was numerically simulated by finite-element method.The effects of processing parameters on the load,strain distribution and temperature field have been analyzed.The results show that the calculated value of load is close to the measured one under different extrusion conditions,the relative error is less than 10%.Even though the billet and die were not heated,the temperature of the extruded billet was increased up to 340 ℃.If only the die was heated to 300 ℃,at the beginning of the extrusion process,the load was up to its maximum value,close to the one of extrusion process at room temperature,and then dropped greatly.The load increases obviously with the increasing of friction factor.When the billet is not heated and the temperature of die is increased gradually,the load changes little at first;and if the die temperature is over about 100 ℃,the load would begin to drop.