The Microtexture and Tensile Properties of Continuous-Wave and Quasi-Continuous-Wave Laser Powder-Deposited Inconel 718

Inconel 718 superalloy has been widely used in the aerospace field. In this study, the effect of linear heat input and laser mode on the microtexture and tensile properties of laser powder-deposited (LPD) Inconel 718 was studied. Continuous-wave (CW) and quasi-continuous-wave (QCW) laser modes were conducted in the experiments. The results showed that under low linear heat input, the microtexture morphologies with CW LPD and QCW LPD were long directional columnar grains and chaotic grains, respectively. The grain size of QCW LPD is finer than that of CW LPD. With the increase of linear heat input, the directivity of microtexture morphology with CW LPD becomes unobvious, while the microtexture morphology of QCW LPD changes little with enlarged grain size. Due to the finer grain size, the tensile strength at 600 ℃ of sample with low linear heat input (60 J/mm) and QCW laser mode is 17.7% higher than that with high linear heat input (120 J/mm) and CW laser mode.