Novel technique to suppress hydrocarbon contamination for high accuracy determination of carbon content in steel by FE-EPMA.
Novel technique to suppress hydrocarbon contamination for high accuracy determination of carbon content in steel by FE-EPMA.
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DOI：
10.1038/srep29825
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发表时间：
2016-07-19
影响因子：
4.6
通讯作者：
Ishida K
中科院分区：
文献类型：
--
作者：
Yamashita T;Tanaka Y;Yagoshi M;Ishida K
在多相钢中，控制各相中的碳含量是合金设计中实现高强度和高塑性的最重要因素。然而，由于测量过程中不可避免的烃类污染的影响，电子探针微分析（EPMA）难以高精度地测定多相结构中的碳含量。我们研究了在现场排放（FE） EPMA测量过程中抑制碳氢化合物污染的新方法以及传统的液氮捕集器。样品室内的等离子体清洁器通过点分析改善了碳含量测定，将精度从以前的0.1质量%C提高到0.01质量%C的十倍。在大约100°C的阶段加热显著抑制污染的增长在连续点测量和绘图。通过以上两种技术的结合，我们成功地实现了双相钢中二维碳分布的可视化。铁素体/马氏体界面处的碳浓度在所有界面处都不相同，存在局部变化。该技术有望成为了解钢的力学性能和微观组织演变机制的有力工具，从而为设计具有优异性能的新型钢产品做出贡献。
In multiphase steels, control of the carbon contents in the respective phases is the most important factor in alloy design for achieving high strength and high ductility. However, it is unusually difficult to determine the carbon contents in multiphase structures with high accuracy by electron probe microanalysis (EPMA) due to the unavoidable effect of hydrocarbon contamination during measurements. We have investigated new methods for suppressing hydrocarbon contamination during field emission (FE) EPMA measurements as well as a conventional liquid nitrogen trap. Plasma cleaner inside the specimen chamber results in a improvement of carbon-content determination by point analysis, increasing precision tenfold from the previous 0.1 mass%C to 0.01 mass%C. Stage heating at about 100 °C dramatically suppresses contamination growth during continuous point measurement and mapping. By the combination of above two techniques, we successfully visualized the two-dimensional carbon distribution in a dual-phase steel. It was also noted that the carbon concentrations at the ferrite/martensite interfaces were not the same across all interfaces, and local variation was observed. The developed technique is expected to be a powerful tool for understanding the mechanisms of mechanical properties and microstructural evolution, thereby contributing to the design of new steel products with superior properties.