Influence of processing parameters on the microstructure and tensile property of 85 W-15Ni produced by laser direct deposition

摘要： The plate-like shape 85W-15Ni parts were produced by laser direct deposition technology with different processing parameters (laser power and scanning speed). The influence of processing parameters and their corresponding laser energy density on the microstructural characterization, phase composition and tensile property of 85W-15Ni samples was investigated. The results show that the relative density of samples increased with the laser energy density and the densification trend started to slow as the laser energy density reached 380-400 J/mm3, though the highest density value was obtained with laser energy of 425 J/mm3. With the increase of laser energy density, more disorder and fine W dendrites existed at the bonding region between deposition layers and more W-W grain boundaries formed at the central region of the layer. The 85W-15Ni samples produced with different processing parameters consisted of W and γ-Ni phase. To improve the tensile property, it is necessary to increase the laser energy density to obtain denser structure and reduce the residual pores or gaps. However, the excessive laser energy density resulted in the formation of more W-W grain boundaries that were detrimental to the tensile property. The best tensile properties were obtained at the laser energy density of 395 J/mm3.