含缺陷的Al-Si-Mg合金的疲劳性能和强度评估

在高速铁路接触网支撑定位装置用Al-7Si-0.6Mg合金中引入不同尺寸的人工缺陷，进行旋转弯曲疲劳实验以定量研究缺陷尺寸对材料疲劳强度的影响，并建立了疲劳强度与缺陷尺寸之间的定量关系。结果表明：材料表面的人工缺陷尺寸越大，试样的高周疲劳强度的下降越大；材料表面尺寸小于370 μm的人工缺陷对其高周疲劳强度没有影响；在适用性条件范围内使用修正的Murakami公式能更加准确地评估Al-7Si-0.6Mg铝合金的高周疲劳强度和应力强度因子门槛范围。

Fatigue Properties and Strength Assessment for Al-Si-Mg Alloy via Test Samples with Artificial Defects

Artificial defects of different size were introduced on rotary bending fatigue test samples of Al-7Si-0.6Mg Al-alloy, which is the desired material for the high-speed railway contact net support and positioning device. The influence of defect sizes on the fatigue strength of the alloy was examined via rotating bending fatigue machine, while the quantitative relationship between fatigue strength and defect size was established. The results show that the larger the artificial defect size, the greater the decrease of the high cycle fatigue strength of the sample. The artificial defect size of less than 370 μm has no effect on the high cycle fatigue strength of the alloy; The modified Murakami formula can be applied for more accurate evaluation of the high cycle fatigue strength and stress intensity factor threshold of Al-7Si-0.6Mg Al-alloy within the range of applicability conditions.