Effect of Ta on the microstructure and hardness of Stellite 6 coating deposited by low power pulse laser treatments
Effect of Ta on the microstructure and hardness of Stellite 6 coating deposited by low power pulse laser treatments
复制标题
DOI：
10.1016/j.surfcoat.2012.10.065
复制
发表时间：
2012-12
影响因子：
5.4
通讯作者：
A. Farnia;F. M. Ghaini;J. Rao;V. Ocelík;J. T. Hosson
中科院分区：
文献类型：
--
作者：
A. Farnia;F. M. Ghaini;J. Rao;V. Ocelík;J. T. Hosson
采用Nd：YAG脉冲激光熔覆技术，在低碳铁素体钢基体上原位合成了不同Ta含量的Stellite 6堆焊合金。采用扫描电镜、能谱仪和透射电镜研究了不同Ta含量对Stellite 6堆焊合金显微组织的影响。随着Ta含量的增加，除了在无Ta的Stellite 6合金枝晶间区域观察到正交晶的富Cr的M7 C3型碳化物外，在碳化铬-钴固溶共晶区还形成了富Ta的M4C3.04型碳化物以及单个粗大的富Ta的MC型碳化物。此外，富Co枝晶变得更细。随着Ta含量的进一步增加，在正交相的界面处形成了六方相的M7 C3碳化物。这些组织变化是Ta改性Stellite 6堆焊合金硬度提高的原因。
Stellite 6 hardfacing alloy with different Ta contents is successfully synthesized with an in situ process on low carbon ferritic steel substrate by Nd:YAG pulsed laser cladding with pre-placed Stellite 6 and Ta mixed powders. The effect of different amounts of Ta on the microstructure of the Stellite 6 hardfacing alloy is investigated using scanning electron microscopy, energy dispersive spectroscopy and transmission electron microscopy. With an increase in Ta content, in addition to orthorhombic Cr-rich M7C3carbides observed in the Ta-free Stellite 6 alloy in interdendritic regions, Ta-rich M4C3.04type carbides are formed as well as individual bulky Ta-rich MC type carbides in Chromium carbide–Cobalt solid solution eutectic area. Furthermore, the Co-rich dendrites become much finer. With further increase of Ta, hexagonal M7C3carbides are formed at the interface of orthorhombic ones. These microstructural changes are responsible for the improvement of the hardness of the Ta modified Stellite 6 hardfacing alloy.