送粉速率对IN718熔覆涂层拉伸性能的影响

张朝铭; 舒林森

doi:10.14158/j.cnki.1001-3814.20222836

送粉速率对IN718熔覆涂层拉伸性能的影响

Effect of Powder Feeding Rates on Tensile Properties of IN718 Cladding Coating

摘要

摘要: 采用单因素变量法，保持扫描速度22 mm/s、激光功率1800 W和光斑直径φ2 mm，研究送粉速率分别在18、20、22 g·min^-1条件下IN718熔覆涂层截面形貌、显微组织、拉伸性能及其断口特征。结果表明：随着送粉速率的增加，熔覆层的组织晶粒尺寸先减小后增大。送粉速率20 g·min^-1时，熔覆层中部、下部组织由具有方向性的小尺寸（30 μm以下）柱状晶和树枝晶构成，此时制备试件的拉伸性能最优，其屈服强度与基材相近、抗拉强度高于基材，两个强度值分别为（1047±45）MPa和（1245±54）MPa，而杨氏模量、伸长率依次为（185±3）GPa、（7.1±0.3）%，拉伸断口呈韧性断裂特征，具有较好的塑性。

Abstract: The single factor variable method was used to study the cross section morphology, microstructure, tensile properties and fracture characteristics of IN718 cladding coating at the feeding rates of 18 g·min^-1, 20 g·min^-1 and 22 g·min^-1, respectively, with the scanning speed of 22mm/s, laser power of 1800W and spot diameter of φ2 mm.The results show that the grain size of the cladding layer decreases first and then increases with the increase of powder feeding rate.When the powder feeding rate is 20 g·min^-1, the middle and lower layers of the cladding layer are composed of directional small size (below 30 μm) columnar crystals and dendrites.At this time, the tensile properties of the specimens prepared are the best, the yield strength is similar to that of the substrate, and the tensile strength is higher than that of the substrate. The two strength values are (1047±45)MPa and(1245±54)MPa, respectively.The Young's modulus and elongation are(185±3)GPa and(7.1±0.3)%, respectively.

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