A356铝合金高周疲劳循环形变分析

ANALYSIS OF HIGH CYCLE FATIGUE DEFORMATION OF A356 ALUMINUM ALLOYS

对A356铝合金高周疲劳循环形变特性及其微观机理进行了研究,表明A356铝合金总体上显示出循环硬化的特征,某些阶段出现循环软化现象。透射电镜分析表明,循环形变现象与A356铝合金循环过程位错组态变化相关,A356铝合金基体的位错组态变化过程为:初始位错网→密集位错网与少量位错线→交叉滑移线→滑移带显著化→明显交叉滑移带,使基体发生循环硬化→循环软化→循环硬化现象。

The cyclic deformation characteristic and micro mechanism of A356 aluminum alloy were studied. The A356 showed cyclic hardening characteristic as a whole, but in some stage it showed cyclic softening characteristic. TEM observation showed that the cyclic deformation behavior related to the variation of dislocation configuration in matrix. The evolution process of dislocation configuration in A356 Al alloy matrix is： dislocation network→dense dislocation network and little slip lines→cross slip lines→slip bands→cross slip bands, which resulted in matrix the cyclic hardening first, then cyclic softening, and cyclic hardening again.