含有第二相的高强铝合金疲劳模型

A Fatigue Model of High Strength Al Alloys Containing Second Phase Particles of Various Sizes

摘要:

基于疲劳裂纹尖端的应力和应变以及高强铝合金中不同尺度第二相性态对其延性的影响，建立了高强铝合金中粗大第二相、中间尺度第二相以及细小时效强化相性态与其疲劳裂纹扩展速率之间的多元非线性关系模型。结果表明：对于2024铝合金的疲劳扩展速率，该模型的预测趋势与他人的实验研究结果吻合良好。同时借助于对该模型的理论分析，提出了在确保高强铝合金强度不降低的前提下降低其疲劳裂纹扩展速率的优化方案。

Abstract:

A model was established for high strength aluminum alloys to describe the elastic/plastic stress and strain at the crack tip fields and the effects of second phase particles with various size scales on tensile ductility. The model presents a multi-element nonlinear relation between the fatigue crack growth rate and the characteristics of constituents, dispersoids, and precipitates within the alloys. Qualitative agreement between experimental and theoretical results is obtained for the fatigue crack growth rates of 2024 Al alloy. Moreover, an optimum scheme to reduce the fatigue crack growth rates and maintain alloy strength could be approached by application of the model.