Following the first and second generation, the challenge in obtaining a better balance between strength and elongation is still the main characteristic of the third generation of Advanced High Strength Steels (AHSS). With this, the use of multiphase microstructures has increased over the last few years. It can be difficult to characterize all the phases with only Optical Microscopy (OM), so the use of Scanning Electron Microscopy (SEM) is essential for accuracy in cases where researchers lack experience. In order to expand the possibilities, this research proposed a new approach that would allow experienced researchers to characterize multiphase steels using only OM. A high silicon steel was austempered slightly below Ms temperature for three different time periods in order to obtain different quantities of martensite, bainite and retained austenite. X-Ray Diffraction (XRD) was carried out in order to confirm and obtain retained austenite volume fractions, and the results indicated that shorter holding times were not enough to enrich and stabilize retained austenite. Then, each samples was etched with four different etchants. Results showed that the new Multiple Etchings Methodology (MEM) allowed a better visualization of all the phases when viewed together. Beraha Martensitc revealed non-tempered martensitic microstructures. Sodium Metabisulfite revealed retained austenite. LePera and Nital were the best at revealing the evolution of the microstructure over time, even with the changes which occurred due to martensite tempering. SEM images confirmed the results obtained via MEM.im This article is protected by copyright. All rights reserved.

中文翻译：

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多重蚀刻方法：多相钢表征的新方法

继第一代和第二代之后，在强度和伸长率之间获得更好平衡的挑战仍然是第三代先进高强度钢 (AHSS) 的主要特征。因此，多相微结构的使用在过去几年中有所增加。仅使用光学显微镜 (OM) 可能难以表征所有相，因此在研究人员缺乏经验的情况下，使用扫描电子显微镜 (SEM) 对准确性至关重要。为了扩大可能性，这项研究提出了一种新方法，使经验丰富的研究人员能够仅使用 OM 表征多相钢。将高硅钢在略低于 Ms 温度的三个不同时间段进行奥氏体回火，以获得不同数量的马氏体，贝氏体和残余奥氏体。进行 X 射线衍射 (XRD) 以确认和获得残余奥氏体的体积分数，结果表明较短的保持时间不足以富集和稳定残余奥氏体。然后，用四种不同的蚀刻剂蚀刻每个样品。结果表明，当一起查看时，新的多重蚀刻方法 (MEM) 可以更好地可视化所有阶段。Beraha Martensitc 揭示了非回火马氏体微观结构。焦亚硫酸钠显示残留奥氏体。LePera 和 Nital 最擅长揭示微观结构随时间的演变，即使是由于马氏体回火而发生的变化。SEM 图像证实了通过 MEM.im 获得的结果 本文受版权保护。版权所有。进行 X 射线衍射 (XRD) 以确认和获得残余奥氏体的体积分数，结果表明较短的保持时间不足以富集和稳定残余奥氏体。然后，用四种不同的蚀刻剂蚀刻每个样品。结果表明，当一起查看时，新的多重蚀刻方法 (MEM) 可以更好地可视化所有阶段。Beraha Martensitc 揭示了非回火马氏体微观结构。焦亚硫酸钠显示残留奥氏体。LePera 和 Nital 最擅长揭示微观结构随时间的演变，即使是由于马氏体回火而发生的变化。SEM 图像证实了通过 MEM.im 获得的结果 本文受版权保护。版权所有。进行 X 射线衍射 (XRD) 以确认和获得残余奥氏体的体积分数，结果表明较短的保持时间不足以富集和稳定残余奥氏体。然后，用四种不同的蚀刻剂蚀刻每个样品。结果表明，当一起查看时，新的多重蚀刻方法 (MEM) 可以更好地可视化所有阶段。Beraha Martensitc 揭示了非回火马氏体微观结构。焦亚硫酸钠显示残留奥氏体。LePera 和 Nital 最擅长揭示微观结构随时间的演变，即使是由于马氏体回火而发生的变化。SEM 图像证实了通过 MEM.im 获得的结果 本文受版权保护。版权所有。