Effects of Processing Residual Stresses on Fatigue Crack Growth Behavior of Structural Materials: Experimental Approaches and Microstructural Mechanisms
Effects of Processing Residual Stresses on Fatigue Crack Growth Behavior of Structural Materials: Experimental Approaches and Microstructural Mechanisms
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加工残余应力对结构材料疲劳裂纹扩展行为的影响：实验方法和微观结构机制
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发表时间：
2011
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影响因子：
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通讯作者：
D. Lados
中科院分区：
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作者：
Christopher J. Lammi;D. Lados
研究了普通结构铝合金6061-T61在低应力场和高应力场作用下长裂纹的疲劳裂纹扩展机制。在热处理期间通过淬火在材料中引入体加工残余应力。在不同应力比下对紧凑拉伸（CT）试样进行疲劳裂纹扩展（FCG）试验，以捕获闭合和Kmax效应。疲劳裂纹扩展机制在微观尺度上的变化与闭合、应力比和塑性有关，这些都取决于残余应力。双参数ΔK-Kmax方法包括裂纹闭合和残余应力的修正，可用于在低残余应力和高残余应力条件下，将微观尺度下的疲劳裂纹扩展机制与不同应力比下的裂纹扩展速率变化联系起来。在这项研究中提出的方法和工具可以用来优化现有的材料和工艺，以及开发新的材料和工艺的FCG有限的结构应用。
Fatigue crack growth mechanisms of long cracks through fields with low and high residual stresses were investigated for a common structural aluminum alloy, 6061-T61. Bulk processing residual stresses were introduced in the material by quenching during heat treatment. Compact tension (CT) specimens were fatigue crack growth (FCG) tested at varying stress ratios to capture the closure and Kmax effects. The changes in fatigue crack growth mechanisms at the microstructural scale are correlated to closure, stress ratio, and plasticity, which are all dependent on residual stress. A dual-parameter ΔK–Kmax approach, which includes corrections for crack closure and residual stresses, is used uniquely to connect fatigue crack growth mechanisms at the microstructural scale with changes in crack growth rates at various stress ratios for low- and high-residual-stress conditions. The methods and tools proposed in this study can be used to optimize existing materials and processes as well as to develop new materials and processes for FCG limited structural applications.