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

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.