Influence of powder surface contamination in the Ni-based superalloy alloy718 fabricated by selective laser melting and hot isostatic pressing

Abstract

The aim of this study was to gain a deep understanding of the microstructure-mechanical relationship between solid-state sintering and full-melting processes. The IN718 superalloy was fabricated by hot isostatic pressing (HIP) and selective laser melting (SLM). Continuous precipitates were clearly localized along the prior particle boundary (PPB) in the HIP materials, while SLM materials showed a microstructure free of PPB. The mechanical properties of specimens that underwent SLM + solution treatment and aging were comparable to those of conventional wrought specimens both at room temperature and 650 ºC. However, a drop was observed in the ductility of HIP material at 650 ºC. The brittle particles along the PPB were found to affect the HIP materials’ creep life and ductility during solid-state sintering.