Abstract Many industrial components made of cast aluminum alloys are subjected to multiaxial loadings, while most of research on these materials are on uniaxial loading condition. This article investigates the fatigue performance of A356-T6 aluminum alloy produced by high pressure die cast (HPDC) under different loading conditions. In addition to obtaining monotonic and cyclic deformation behaviors, fatigue tests were performed under axial, torsion, in-phase and out-of-phase combined loadings. In order to study the fatigue crack growth mechanism, few tests were also conducted under cyclic torsion with static tension or compression. It was observed that the fatigue cracks in all specimens initiated from defects, mainly porosity, and grew on the plane of maximum principal stress. Smith-Watson-Topper (SWT) damage parameter was used to correlate the fatigue data. The experimental fatigue life data were predicted using small crack growth models and from the crack initiating defect on the fracture surfaces. The fatigue lives under different loading conditions were also predicted using the maximum defect size estimated by extreme value statistics. Very good agreements with the experimental lives under different loading conditions were obtained.

中文翻译：

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轴向、扭转和多轴载荷下铸铝的疲劳性能和寿命预测

摘要 铸造铝合金制成的许多工业部件都承受多轴载荷，而对这些材料的研究大多是在单轴载荷条件下进行的。本文研究了高压压铸(HPDC)生产的A356-T6铝合金在不同载荷条件下的疲劳性能。除了获得单调和循环变形行为外，还在轴向、扭转、同相和异相组合载荷下进行了疲劳试验。为了研究疲劳裂纹扩展机制，在循环扭转和静态拉伸或压缩下也进行了很少的测试。观察到所有试样中的疲劳裂纹均起源于缺陷，主要是孔隙，并在最大主应力平面上扩展。Smith-Watson-Topper (SWT) 损伤参数用于关联疲劳数据。实验疲劳寿命数据是使用小裂纹扩展模型和断口上的裂纹起始缺陷预测的。还使用通过极值统计估计的最大缺陷尺寸来预测不同载荷条件下的疲劳寿命。获得了与不同负载条件下的实验寿命非常一致的结果。