Influence of Defects on High-Temperature Oxidation Performance of Gh3536 Superalloys Fabricated by Laser Powder Bed Fusion

Abstract

This study investigates the formation of defects and their impact on oxidation behaviour of GH3536 superalloys fabricated by laser powder bed fusion (LPBF). Defects of six series of samples manufactured by different parameters is dominated by pores, micro-cracks, and lack of fusion, respectively. The superalloy is isothermally oxidised in 950 °C dry air for 500 h. The oxidation resistance of LPBF GH3536 depends on the types and quantity of processing defects, wherein the sample with micro-cracks as the main defect exhibit the worst oxidation resistance. Electron probe microanalysis of the superalloy revealed the impact of micro-cracks on diffusion process. Defects seriously deteriorate the oxidation resistance, especially micro-crack defects. Reducing manufacturing defects in the samples can improve the corrosion resistance.

Keywords: superalloy, laser powder bed fusion, defects, high-temperature oxidation, electron probe microanalysis, microstructure