IN625合金激光熔覆修复EA4T钢显微组织及力学性能研究

Microstructure and Mechanical Properties of EA4T Steel Repaired by Laser Cladding IN625 Alloy

摘要:

选用IN625高温合金作为修复原材料，对EA4T车轴钢表面进行激光增材修复研究，通过X射线衍射仪、扫描电子显微镜、维氏硬度计以及万能实验机分析了IN625激光熔覆试样不同区域相组成、显微组织及晶粒尺寸，并测试了其力学性能。结果表明：IN625激光熔覆层底部为多种生长方向的柱状晶组织，中部为单一生长方向的柱状晶组织且晶粒尺寸 最大，顶部为以等轴晶为主的杂晶区域；熔覆层和基体发生了Ni、Cr和Fe元素的互扩散作用，扩散区域大约为9 μm；IN625激光熔覆试样综合力学性能远高于EA4T基体材料，显微硬度达到295 HV_0.2、抗拉强度达到888 MPa、延伸率 达到38.0%。

Abstract:

IN625 superalloy was used to repair the surface of EA4T axle steel by laser cladding. The phase composition, microstructure, grain size and mechanical properties of different areas of IN625 laser cladding samples were analyzed by X-ray diffractometer, scanning electron microscope, Vickers hardness tester and universal experimental machine, respectively. The results show that the bottom of the IN625 laser cladding layer is the columnar crystal structure with multiple growth directions, the middle is the columnar crystal structure with single growth direction and the grain size is the largest, and the top is the mixed crystal region dominated by equiaxial crystal. The interdiffusion of Ni, Cr and Fe occurs between the cladding layer and the substrate, and the diffusion region is about 9 μm. The microhardness is 295 HV_0.2, the tensile strength is 888 MPa and the elongation is 38.0%.