【摘要】 对LY12铝合金的拉扭复合加载疲劳性能进行了研究,并用扫描电镜对疲劳试样的断口进行了观察。试验选用单轴轴向、0°同相拉扭复合、45°非同相拉扭复合、90°非同相拉扭复合和纯扭转五种加载路径,并使试样在不同加载路径下的最大等效应变值相等。结果表明,LY12铝合金试样在五种加载条件下,均出现循环硬化和饱和现象。LY12铝合金试样在纯扭转加载时的寿命最长,在90°非同相拉扭复合加载时的寿命最短。用W ang-B rown模型的损伤参量,可以较好解释不同加载条件的疲劳寿命差异。单轴轴向加载和0°同相拉扭复合加载试样的断口均出现疲劳条纹,纯扭转加载和90°非同相拉扭复合加载断口形貌以裂纹面间相互摩擦的痕迹为主。更多还原

【Abstract】 Fatigue properties of LY12 aluminum alloy samples under combined tension and torsion were investigated,and the fracture surfaces were observed through scanning electron microscopy.Axial tensioncompression,0° in-phase combined tension and torsion,45° out-of-phase combined tension and torsion,90° out-of-phase combined tension and torsion and fully reversed torsion loading paths were selected,and the same maximum effective strain was kept for the five loading paths.Cyclic hardening and saturation were observed under five loading paths.The fatigue life is the longest under fully reversed torsion and the shortest under 90° out-of-phase combined tension and torsion.The difference in fatigue life under five loading paths can be explained through Wang-Brown damage parameter.Fatigue striations can be seen on the fracture surfaces of samples under axial tension-compression and 0° in-phase combined tension and torsion,and extensive rubbing is apparent on the fracture surface of samples under 90° out-of-phase combined tension and torsion and fully reversed torsion.更多还原