Microstructural Fatigue Crack Growth in Single-Packet Structures of Ultra-Low Carbon Steel Lath Martensite
Microstructural Fatigue Crack Growth in Single-Packet Structures of Ultra-Low Carbon Steel Lath Martensite
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DOI：
10.1016/j.scriptamat.2019.08.004
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发表时间：
2019-07
期刊：
影响因子：
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通讯作者：
Shohei Ueki;T. Matsumura;Y. Mine;Kazushige Morito;K. Takashima
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文献类型：
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作者：
Shohei Ueki;T. Matsumura;Y. Mine;Kazushige Morito;K. Takashima
采用超低碳钢小型紧凑拉伸试样，研究了不同惯习面取向的单束结构疲劳裂纹扩展行为，以阐明板条马氏体微观裂纹扩展的基本过程。疲劳裂纹的扩展速率在沿着块体边界扩展时比在跨块体扩展时高，而两种裂纹的断裂表面都是波纹状的。疲劳试验后的电子显微镜结果表明，裂纹倾向于增长沿着块边界与高滑移对称性，而不是采取迂回路线通过细胞边界形成由于激活位错与预先存在的块内位错的相互作用。
Fatigue crack growth in single-packet structures with different habit-plane orientations was examined using miniature compact-tension specimens of ultra-low carbon steel to elucidate the elementary process of microstructural crack growth in lath martensite. The growth rates of fatigue cracks were higher in propagating along block boundaries than in running across blocks, while both cracks had a rippled fracture surface. Post-fatigue-test electron microscopy results suggest that the crack prefers to grow along the block boundaries with high slip symmetry rather than take a roundabout route through the cell boundaries formed owing to the interaction of activated dislocations with pre-existing dislocations inside blocks.