The Influence of Microstructural Morphology and Prestrain on Fatigue Crack Propagation of Dual-phase Steels in the Near-threshold Region
The Influence of Microstructural Morphology and Prestrain on Fatigue Crack Propagation of Dual-phase Steels in the Near-threshold Region
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组织形貌和预应变对双相钢近阈值区疲劳裂纹扩展的影响
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
T. Miyata
中科院分区：
文献类型：
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作者：
Katsumi Nakajima;Susumu Kamiishi;M. Yokoe;T. Miyata
研究了不同显微组织形态的双相钢在门槛值附近的疲劳裂纹扩展过程中显微组织和预应变的影响。马氏体相弥散分布在铁素体基体中的材料比马氏体相连续分布在铁素体晶粒周围的材料具有更高的名义应力强度范围和更低的裂纹扩展速率。疲劳试验前的预应变导致两种材料的标称应力强度范围减小。然而，在有效应力强度范围内，所有材料之间略有差异。显微组织形貌和预应变对裂纹路径有很大影响，导致裂纹闭合差异较大。裂纹闭合程度与疲劳断口表面粗糙度之间存在定量关系。
The influence of microstructure and prestrain on fatigue crack propagation in the near threshold region was studied for dual-phase steels with different microstructural morphologies. The material with martensite phases dispersed in ferrite matrix exhibited a higher nominal stress intensity range and a lower crack propagation rate than those of material with a continuous martensite phase around ferrite grains. Prestrain prior to fatigue testing resulted in a decrease of nominal stress intensity range in both materials. However there was a slight difference among all the materials in the effective stress intensity range. The microstructural morphology and prestrain exerted a great influence on crack path and that caused a large difference in crack closure. A quantitative correlation existed between crack closure level and surface roughness of fatigue fracture.