(大连理工大学 材料工程系， 大连 116023)
摘 要: 选用合适的激光工艺参数及涂层成分，利用激光熔覆工艺在45＃钢表面制备了原位析出Fe-Ti-B复合材料涂层。远离平衡态的激光表面处理工艺使涂层中原位析出了一定数量的不同于稳定相的亚稳定相。 利用X射线衍射（XRD）、 透射电镜(TEM)等手段对涂层的显微组织及相结构进行了研究。 结果表明：涂层中主要含有呈块状、 条状、 颗粒状或团絮状分布的Fe2B(Fe3B)/α-Fe和TiB2(TiB)/α-Fe低熔点共晶或离异共晶组织； 原位共晶相析出时与基体保持某种最合理的空间取向， 在α-Fe基体与原位析出相界面上存在隐约可见的位错堆积。
关键字: 激光熔覆； Fe-Ti-B; 原位析出； 涂层； 显微组织
（ Department of Materials Engineering，
Dalian University of Technology， Dalian 116023, China）
Abstract: In-situ precipitating Fe-Ti-B composite coating was fabricated on 45# steel surface by laser cladding with optimal laser parameters and coating compositions. A certain amount of metastable phases differing from the stable phases were obtained through laser surface modification which deviates from the equilibrium state. The microstructure of the coating was studied by X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The results show that the coating mainly contains Fe2B(Fe3B)/α-Fe and TiB2(TiB)/α-Fe low melting point eutectic or divorced eutectic presenting block, strip, granular and wadding shape. The in-situ eutectic phases and the matrix have a certain optimal orientation relationship as they precipitate. The faint dislocation tangle lies at the interface between the matrix and the in-situ precipitating phases.
Key words: laser cladding; Fe-Ti-B; in-situ precipitating; coating; microstructure
