激光熔覆Fe_3Al涂层的工艺与组织结构研究

Study on Preparing and Microstructure of the Fe_3Al Intermetallic Compound Coatings by Laser Cladding

以Fe3A1粉末为原料，采用激光熔覆工艺在低碳钢基体的表面制备了Fe3Al金属间化合物涂层。研究了激光熔覆功率对涂层质量的影响，实验在2．4～2．6 kW功率下获得了良好的熔覆效果，涂层致密、无肉眼可见气孔、夹杂、无宏观裂纹并与基体完全冶金结合；涂层组织为粗大的块状晶团，晶团由微细片状Fe3Al相构成，电子衍射分析测定Fe3Al晶格常数为0．542 nm；Fe3Al熔覆涂层的硬度为350-420 HV，较铸态Fe3Al明显提高。

Fe3 AI intermetallic compound coatings were prepared on mild steel with Fe3 A1 powders by laser cladding. The influ-ence of laser powers to layers quality was discussed, and good quality coatings were acquired with 2.4-2.6 kW powers in thiswork. The results show that the coating of Fe3 A1 joints metallurgically with the steel, with no pore, no inclusion and cracks inmacroscopic. The coating consists mainly of Fe3 AI phase, and the microstructure of the layer consists of massive grain-groups,with the grain-groups consist of banding fine Fe3A1 phase. The lattice constant of Fe3 A1 is 0. 542 nm by electronic diffraction.The hardness values of coatings are about 350-420 HV, which are higher obviously than that of the casting Fe3 AI alloy.