Determination of Three-Dimensional Morphology and Inner Structure of Second-Phase Inclusions in Metals by Non-Aqueous Solution Electrolytic and Room Temperature Organic Methods
Determination of Three-Dimensional Morphology and Inner Structure of Second-Phase Inclusions in Metals by Non-Aqueous Solution Electrolytic and Room Temperature Organic Methods
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DOI：
10.3390/met8010068
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发表时间：
2018-01-01
期刊：
影响因子：
2.9
通讯作者：
Yang, Wensheng
中科院分区：
文献类型：
--
作者：
Guo, Jing;Fang, Keming;Yang, Wensheng
金属中的二次相颗粒，特别是由非金属材料组成的二次相颗粒，往往对金属的机械性能不利；因此，控制夹杂物的形成和生长至关重要。挑战之一是确定此类包裹体的三维形态和内部结构。本研究基于电化学原理，开发了非水溶液电解法和室温有机技术，测定铝镇静钢、硅镇静钢和球墨铸铁中非金属夹杂物的三维形貌和内部结构。首先在不损伤包裹体的情况下提取包裹体，然后通过铜离子沉积对收集到的包裹体进行包裹和切割。结果表明，铝镇静钢中的夹杂物形态不规则，硅镇静钢中的夹杂物主要为球形，球墨铸铁中的球状石墨几乎全部呈均匀的球状形态。此外，铝镇静钢的夹杂物内部组织中未观察到形核，而硅酸盐夹杂物表面出现了一些树枝状或棒状MnS相析出，并且在其内部基体中检测到了一些富硅酸盐相。对于球状石墨，几乎每个石墨颗粒的中心都观察到稀土氧化物（一个或多个颗粒）作为核。通过这两种开发的方法可以更好地理解这些类型金属中夹杂物的形成和演变。
The secondary-phase particles in metals, particularly those composed of non-metallic materials, are often detrimental to the mechanical properties of metals; thus, it is crucial to control inclusion formation and growth. One of the challenges is determining the three-dimensional morphology and inner structures of such inclusions. In this study, a non-aqueous solution electrolytic method and a room-temperature organic technique were developed based on the principle of electrochemistry to determine the three-dimensional morphologies and inner structures of non-metallic inclusions in Al-killed steel, Si-killed steel, and ductile cast iron. The inclusions were first extracted without any damage to the inclusions, and then the collected inclusions were wrapped and cut through Cu ion deposition. The results revealed that the inclusions in Al-killed steel had an irregular morphology, that those in the Si-killed steel were mainly spherical, and that almost all the spheroidal graphite in the ductile cast iron featured a uniform globular morphology. In addition, nucleation was not observed in the inner structures of the inclusions in the Al-killed steel, while some dendritic or rod-like MnS phase precipitates appeared on the silicate inclusion surfaces, and some silicate-rich phases were detected in their inner matrix. For spheroidal graphite, rare-earth oxides (one particle or more) were observed as nuclei in the center of almost every graphite particle. The formation and evolution of inclusions in these types of metals can be better understood by means of the two developed methods.