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本文简要地评述了铝合金、钛合金和高强度钢的疲劳裂纹扩展机制及其工程应用;提出了预测疲劳裂纹扩展门槛值的一个普遍关系式;评价了现有四种超载模型对Ti-6A1-4V合金在拉伸超载下的延缓效应和预测寿命能力。对Willenborg和Maarse模型作了改进,并应用于A1和Ti合金的寿命预测。改进后的Maarse模型明显地提高了预测拉伸超载下和谱载下寿命的精度。文中还讨论了显微组织、应力比和表面状态等对材料疲劳裂纹扩展行为的影响。
This article briefly reviews the fatigue crack growth mechanism and its engineering application of aluminum alloys, titanium alloys and high-strength steels. A general formula for predicting the fatigue crack growth threshold value is proposed. The effects of four existing overloading models on Ti-6A1 -4V Alloy under Tensile Overload and Prediction of Lifetime Capacity. The Willenborg and Maarse models are improved and applied to the life prediction of A1 and Ti alloys. The improved Maarse model significantly improves the accuracy of predicting the life under tension overloading and under the spectrum. The effects of microstructure, stress ratio and surface condition on the fatigue crack growth behavior are also discussed.