EA4T钢表面激光熔覆Fe314合金熔覆层的微观组织及性能

Microstructure and properties of Fe314 alloy cladding layer by laser cladding on EA4T steel

在EA4T钢表面激光熔覆Fe314合金熔覆层,采用金相显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)、X射线衍射(XRD)及显微硬度仪研究熔覆层微观组织及物相结构,并分析熔覆试样的力学性能。结果表明,Fe314合金熔覆层成型良好,无缺陷。熔覆层底部组织由平面晶与平面晶上方垂直于界面生长的粗大树枝晶组成,中部与上部组织以交叉树枝晶为主。熔覆层主要由奥氏体枝晶与枝晶间的(Cr、Fe)7C3相组成。熔覆层的显微硬度值高于基体,熔覆试样抗拉强度升高,但塑性韧性降低。冲击试样断口熔覆层为宏观上解理断裂,微观上局部准解理断裂的混合断裂机制,基体为宏观上小孔聚集型断裂,微观上准解理断裂的韧性断裂机制。

Laser cladding Fe314 alloy on EA4 T steel substrate,the microstructure of the cladding layer and mechanical properties was analyzed by optical microscope（OM）,scanning electron microscope（SEM）,energy dispersive X-ray diffraction（EDS）,X ray diffraction（XRD） and microhardness tester. The experimental results show that the Fe314 alloy cladding layer is well formed and has no defects. The microstructures of bottom region of cladding layer are mainly planar crystal and coarse dendrites which is perpendicular to the growth of the interface in the plane crystal,in the middle and upper part of cladding layer the main structure is cross dendritic crystal. Cladding layer is mainly composed of austenitic dendrites and（Cr,Fe）7C3 phase of interdendritic. Microhardness of Cladding layer value is higher than the substrate,and the cladding specimen tensile strength increases,but plastic toughness reduces.Impact fracture of cladding layer performance for the cleavage fracture in macro and quasi-cleavage crack in micro. Impact fracture of substrate performance for the small hole aggregation type fracture in macro and quasi-cleavage crack in micro.