热等静压对圆形加载路径下A319铝合金多轴疲劳特性的影响

采用MTS809拉扭复合疲劳试验机、扫描电镜(SEM)研究了热等静压(Hot isostatic pressing,HIP)处理前后,圆形加载路径下,A319铝合金多轴疲劳特性。结果表明,HIP处理后,材料中的孔洞缺陷数量减少,疲劳失效过程中产生的微裂纹的数量减少且尺寸减小。相同等效应变幅值下产生的轴向应力幅值、切向应力幅值、等效应力幅值均显著增加。材料轴向上表现为先产生循环硬化而后循环软化,切向则表现为先产生循环硬化后趋于循环稳定,HIP处理前后循环软化硬化趋势大致相同。轴向应力应变滞后回线、切向扭矩扭角滞后回线面积有所降低,附加强化效果增强。

Effect of Hot Isostatic Pressing on Multiaxial Fatigue Properties of A319 Aluminum Alloy Under Circular Loading Condition

The multiaxial fatigue properties of A319 aluminum alloys with and without hot isostatic pressing (HIP) treatment under circular loading condition were investigated by MTS809 axial/torsional test system and SEM. The results indicate that HIP decreases the sizes and numbers of holes and micro cracks formed during fatigue. Under the same equivalent strain amplitude, HIP increases axial stress, shear stress and equivalent stress amplitudes. Both HIPed and non-HIPed materials show the character of initial cyclic hardening followed by cyclic softening in the axial direction and a trend of initial cyclic hardening followed by a stable tendency in the shear direction, respectively. HIP reduces the areas of the stress-strain hysteresis loops and torque-rotation hysteresis loops and produces additional hardening effect.