采用激光熔注(LMI)技术在Q235钢表面制备WC颗粒增强的金属基复合材料(MMC)层。在激光熔注工艺特性和熔注层宏观特征分析的基础上, 采用X射线衍射(XRD)和扫描电镜(SEM)对激光熔注层微观组织结构进行了分析。结果表明, WC颗粒注入到熔池的整个深度和宽度范围内, 并且在熔注层中的分布比较均匀。WC颗粒的加入改变了熔池的化学成分, 熔注层中出现了新相Fe3W3C。在熔注层上部存在较多Fe3W3C枝晶和少量枝晶间共晶, 在熔注层下部枝晶数量减少, 共晶数量明显增多。激光熔注层中不同WC颗粒周围反应层的尺寸和形貌存在很大差别。WC颗粒注入位置是决定反应层尺寸的重要因素。

Laser melt injection (LMI) was used to produce WC particulate reinforced metal matrix composites (MMC) layers on Q235 steel. Based on the analysis of the LMI process characteristic and the macrostructure of the MMC layer, the MMC layer was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that WC particles can be injected into the whole region of the melted pool and distribute uniformly in the MMC layer. New phase of Fe3W3C is observed in the MMC layer due to the injection of WC particles. The microstructure of the MMC layer is quite complicated and can roughly be divided into two regions: the top part and the bottom part. The microstructure in the top part is characterized by many Fe3W3C dendrites surrounded by few interdendrite eutectics. In the bottom, the amount of Fe3W3C dendrites decreases while eutectics increase obviously. The size and morphology of reaction layers around different WC particles inside the MMC layer exhibit obvious difference. Moreover, the particle injection position plays a critical role in the thickness of the reaction layer.