Effect of SLM process parameters on microscopic defects and surface quality of GH3536 superalloy

Abstract

GH3536 superalloy was fabricated using Selective Laser Melting (SLM) to investigate the effect of process parameters including the laser power and scanning speed on the density, microscopic defects and surface quality of GH3536 samples. According to the measurement of density, it can be found that the density of samples increases rapidly when the laser energy density is less than 57.0 J/mm3, the density of samples fluctuates within the range of 8.30 g/cm3-8.35 g/cm3 as the laser energy density increases from 57.0 J/mm3 to 187.0 J/mm3, while the density of samples decreases slightly when the laser energy further increases. The conclusion is that the inadequate or excessive energy input reduces the density of samples. The metallographic observation shows that there are a large number of lack-of-fusion defects when the laser energy is insufficient. However, when the input laser energy is too much, many evenly distributed microcracks and gas pores appear inside of samples, indicating that defects are the main reason for low density of samples. The optimal process parameters of SLM-processed GH3536 alloy are determined by the statistical analysis of spatter particles which might cause irregular defects. Tensile properties of the sample fabricated under 175 W and 700 mm/s are tested at room temperature and the results show that the SLM-ed GH3536 superalloy has good tensile properties at room temperature.

Keywords

• selective laser melting
• gh3536 superalloy
• process parameter
• microscopic defects
• surface quality