采用Gleeble-1500热模拟机在温度250～400℃、应变速率0.001～1s~(-1)、最大变形程度105%的条件下对ZK60镁合金进行了高温压缩模拟实验研究.分析了实验合金在高温变形时的流变应力和应变速率及变形温度之间的关系,计算了变形激活能和应力指数,并观察了热压缩变形过程中组织的变化.结果表明,合金的峰值流变应力随应变速率的增大而增加,随温度的升高而减小;在给定的变形条件下,计算出合金的变形激活能为63～130kJ/mol,应力指数为2.78～3.79;降低变形温度和提高应变速率可使再结晶晶粒的平均尺寸减小.
Hot compression tests of ZK60 magnesium alloy are performed on Gleeble-1500 thermal simulator testing machine at temperatures ranging from 250℃ to 400℃ and strain rates between 0.001s~(-1) and 1s~(-1).The relationship between flow stress and deformation temperature as well as strain rate is analyzed and the deformation activation energy and stress exponent are calculated.The strained microstructure of the alloy is characterized by optical microscope after compression deformation.It is shown that the peak flow stress increases with an increase of strain rate at constant temperature,and becomes lower with elevating deformation temperature at constant strain rate.The deformation activation energy of 63～130kJ/mol and the corresponding stress exponent of 2.78～3.79 are determined respectively.The average dynamically recrystallized grain size reduces with decreasing temperature and increasing strain rate.
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