Ductility of Advanced High-Strength Steel in the Presence of a Sheared Edge
Ductility of Advanced High-Strength Steel in the Presence of a Sheared Edge
复制标题
存在剪切边缘的先进高强度钢的延展性
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
M. Chen
中科院分区：
文献类型：
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作者：
Tim Ruggles;S. Cluff;M. Miles;D. Fullwood;C. Daniels;Alex Avila;M. Chen
研究了双相（DP） 980和相变诱导塑性（TRIP）辅助贝氏体铁素体（TBF） 980钢在剪切边存在下的延展性。试样在标准测试架和原位扫描电子显微镜（SEM）下进行单轴拉伸测试。在扫描电镜中进行增量拉伸应变，并在每次应变增量时拍摄图像。然后利用数字图像相关技术（DIC）计算微观组织中各相水平的有效应变。应变后的TBF试样出现了跨多个相的剪切带，而DP试样则表现出更多的拼凑应变模式，高应变集中在铁素体中，低应变集中在马氏体中。采用两点统计方法对DIC工作的应变数据和相应的显微组织图像进行分析，评价相硬度对局部化和断裂的影响。与TBF 980相比，DP 980材料在硬相周围有更大的局部化倾向。这至少部分解释了TBF材料的更大延展性，特别是在存在剪切边缘的试样中。
The ductility of dual-phase (DP) 980 and transformation-induced plasticity (TRIP) assisted bainitic ferritic (TBF) 980 steels was studied in the presence of a sheared edge. Specimens were tested in uniaxial tension in a standard test frame as well as in situ in the scanning electron microscope (SEM). Incremental tensile straining was done in the SEM with images taken at each strain increment. Then digital image correlation (DIC) was used to compute the effective strain at the level of the individual phases in the microstructure. Shear banding across multiple phases was seen in strained TBF specimens, while the DP specimens exhibited more of a patchwork strain pattern, with high strains concentrated in ferrite and low strains observed in the martensite. Two-point statistics were applied to the strain data from the DIC work and the corresponding microstructure images to evaluate the effect of phase hardness on localization and fracture. It was observed that the DP 980 material had a greater tendency for localization around hard phases compared to the TBF 980. This at least partially explains the greater ductility of the TBF material, especially in specimens where a sheared edge was present.