铁基自熔合金光束熔覆层的微观组织及强化机理

Microstructure and Strengthening Mechanism of Light Beam Cladding Layer with Iron-based Self-fluxing Alloy Powder

采用SEM、EDS、X射线衍射及显微硬度和洛氏硬度分析手段研究了铁基自熔合金粉末光束熔覆层的微观组织及其物相组成。结果表明 ,Fe Ni Cr B Si系合金粉末的光束熔覆层微观组织由固溶了大量Cr、及少量B、Si、C的γ(Fe,Ni)树枝晶 ,枝晶间(Cr,Fe) 7(C ,B) 3+γ(Fe,Ni)共晶所构成。光束熔覆层的宏观硬度达HRC4 7.3 ,高于同种材料喷涂层及TIG熔覆层的硬度。Cr、Si元素在γ相中的固溶 ,枝晶间共晶 (Cr,Fe) 7(C ,B) 3高硬度相的析出是光束熔覆层得以强化的主要原因。

The microstructure and phase structure of light beam cladding layer with iron-based self-fluxing alloy powder were studied by SEM, EDS, X-ray diffraction, microhardness analysis and Rockwell hardness analysis. The results show that the microstructure of Fe-Ni-Cr-Si-B alloy powder light beam cladding layer is composed of γ(Fe,Ni) dendrite which dissolves a lot of Cr and little B, Si, C, and (Cr,Fe)7(C,B)3+γ(Fe,Ni) eutectic among dendrite. The macrohardness of the light beam cladding layer reaches HRC 47.3, which is higher than that of spraying layer or TIG cladding layer with the same powder. The main reason of strengthening of the light beam cladding layer is the solution of Cr, Si elements of γ phase and the precipitation of high hardness (Cr,Fe)7(C,B)3.