工艺参数对激光熔覆层组织的影响
Effect of Technological Parameters on Microstructure of Ni-based Alloy Coating by Laser Surface Remelting
袁庆龙, 冯旭东, 曹晶晶, 苏志俊
作者单位：(河南理工大学 材料科学与工程学院, 河南 焦作 454000)
中文关键字：激光重熔； Ni25； 工艺参数； 显微组织
英文关键字：laser surface remelting; Ni25; technological parameters; microstructure
中文摘要：采用热喷涂方法在Q235钢表面预置Ni25涂层，研究了激光重熔过程中工艺参数对熔覆层组织的影响；用光学显微镜(OM)观察了涂层横截面的显微组织。结果表明：经过激光重熔后的熔覆层与基体之间形成了良好的冶金结合，其组织组成物包括γ-固溶体，硼化物、碳化物+γ -固溶体的共晶，初晶及共晶的合金渗碳体。在其他工艺参数不变的条件下，随扫描速度的增大，熔覆层组织变得细小、均匀；随激光功率的增大，熔覆层组织变化由块状组织到细小的树枝晶组织，再到粗大的胞状晶组织。
英文摘要：Ni25 coating was prepared on Q235 steel substrate by thermal spraying and laser remelting process. The effects of technological parameters on microstructure were researched. Cross-section morphology of the coating was observed with optical microscope. The results show that there is an excellent metallurgical bonding between the coating and the substrate. The microstructure of the coating is mainly composed of γ-solid solution, boride, carbide + γ-solid solution eutectic, primary alloy cementite and eutectic alloy cementite. Under the conditions of other technological parameters unchanged, the microstructure of the coatings becomes smaller and more homogeneous with laser scanning speed increasing. With laser power increasing, the microstructure changes from block to small dendrite, to thick cellular crystal.