【摘要】 利用Gleeble-1500D对硼酸铝晶须增强镁合金AZ91D复合材料(Al18B4O33w/AZ91D)在温度为300℃~400℃、应变速率为0.001s-1~0.1s-1、最大应变量为0.5的条件下进行高温压缩实验研究,根据真应力-应变曲线,计算出复合材料的Arrhenius型双曲正弦本构方程及应变速率敏感指数m、变形激活能Q。研究表明,晶须的偏转与折断使复合材料应变软化较合金明显,进入稳态变形后流变应力持续下降;峰值应力与变形温度、应变速率之间的关系在低应力区、高应力区分别符合指数关系、幂指数关系,而在全应力区符合双曲正弦关系;晶须的加入使复合材料的m、Q值均高于基体镁合金。更多还原

【Abstract】 The hot compressive behavior at different temperature (300℃～400℃) and strain rate (0.001s-1~0.1s-1) of Al18B4O33w/AZ91D was investigated by use of Gleeble -1500D thermal simulation testing machine and the constitutive parameters were identified through the experiments.The strain rate sensitivity exponent(m) and apparent activation energy(Q) of the selected composite were determined according to true stress-strain curves.The results show that the flow stress decrease continually after the peak stress because of strain softening caused by whisker rotation and breakage.The exponential form represents high stress regime,the power form represents the low stress regime and the hyperbolic sine form represents all stress regime.The value of m and Q of composite are both higher than the matrix alloy because of the addition of Al18B4O33 whisker.更多还原