Effect of pack-chromizing temperature on microstructure and performance of AISI 5140 steel with Cr-coatings
Effect of pack-chromizing temperature on microstructure and performance of AISI 5140 steel with Cr-coatings
复制标题
渗铬温度对镀铬AISI 5140钢组织和性能的影响
DOI：
10.1016/j.surfcoat.2018.03.099
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发表时间：
2018-06-25
影响因子：
5.4
通讯作者：
Yao, Zhongwen
中科院分区：
文献类型：
--
作者：
Hu, Jianjun;Zhang, Yuqing;Yao, Zhongwen
采用感应加热渗铬法在AISI 5140钢表面制备了两种不同的渗铬层。采用X射线衍射（XRD）、背散射电子成像（BSEI）、能谱（EDS）和电子背散射衍射（EBSD）等技术对样品的物相和微观结构进行了表征。结果表明，渗铬温度对渗铬层的相组成和组织结构有很大的影响。在低温（1000摄氏度）下，铬涂层是一种合金珠光体。当温度上升到1300 ℃时，铬涂层变成Cr-Fe固溶体（Cr-Fe SS）。合金珠光体涂层的几何必需位错密度高于钢基体，而块状Cr-Fe SS涂层的几何必需位错密度低于钢基体。与低温形成的合金珠光体涂层相比，高温形成的Cr-Fe SS涂层具有更高的硬度和更好的耐腐蚀性，但延展性较差。揭示了这两种不同类型涂层的形成机制，并讨论了涂层与基体之间位错密度差异的原因。
Two different types of Cr-coatings were prepared on the AISI 5140 steel at different temperatures via induction heating chromizing (IHC). Their phases and microstructures were characterized by X-ray diffraction (XRD), backscattering electron imaging (BSEI), energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) techniques. The results show that the phase and microstructure of the Cr-coatings are highly dependent on the chromizing temperature. At low temperature (1000 degrees C), the Cr-coating is an alloy pearlite. As the temperature rises to 1300 degrees C, the Cr-coating becomes a Cr-Fe solid solution (Cr-Fe SS). Alloy pearlite coating has a higher density of geometrically necessary dislocations (GNDs) than the steel substrate, while the bulk Cr-Fe SS coating has a less density of GNDs than the steel substrate. The Cr-Fe SS coating formed at high temperature has a higher hardness and better corrosion resistance but poorer ductility compared with the alloy pearlite coating developed at low temperature. The formation mechanisms of these two distinct types of coatings were revealed, and the cause of the difference in dislocation density between the coating and the substrate was discussed.