Abstract

An in-situ analysis of local strain accommodation on transformation induced plasticity (TRIP) aided multi-phase steel was performed with a correlative application of characterization techniques such as digital image correlation (DIC), electron backscatter diffraction (EBSD), and micro-mechanical testing. The local strain on the complex microstructure of the multi-phase steel was measured during a tensile test using an innovative DIC method (which does not employ artificial patterns), in conjunction with a scanning electron microscope. The constituent phases of the examined surface were identified by postprocessing implemented on the EBSD maps. This was further verified by nano-indentation, consequently enabling systematic and quantitative analyses of the strain partitioning between the phases. Soft acicular ferrite accommodated the largest strain with sites of intense strain localization around the hard, neighboring martensite. The retained austenite transformed gradually into martensite because of the applied strain and caused strain localization in the neighboring acicular ferrite. This verified that DIC method proposed in this study enables precise and effective data collection at the interfaces between different phases that could have certainly been blocked by the DIC patterns in the conventional method.

Graphic Abstract

中文翻译：

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使用原位 EBSD 拉伸测试和数字图像相关性对多相钢进行应变分析

摘要

结合数字图像相关 (DIC)、电子背散射衍射 (EBSD) 和微机械等表征技术的相关应用，对相变诱导塑性 (TRIP) 辅助多相钢进行了局部应变调节的原位分析测试。在拉伸试验期间，使用创新的 DIC 方法（不采用人工图案）结合扫描电子显微镜测量了多相钢复杂微观结构上的局部应变。通过在 EBSD 地图上实施的后处理来识别检查表面的组成相。这通过纳米压痕进一步验证，因此能够对相之间的应变分配进行系统和定量分析。软针状铁素体适应了最大的应变，在坚硬的相邻马氏体周围具有强烈的应变局部化位置。由于施加的应变，残余奥氏体逐渐转变为马氏体，并在相邻的针状铁素体中引起应变局部化。这证实了本研究中提出的 DIC 方法能够在不同相之间的界面上进行精确有效的数据收集，而这些界面肯定会被传统方法中的 DIC 模式所阻挡。

图形摘要