Effects of Defects and Inclusions on the Fatigue Properties of Inconel 718 Fabricated by Laser Powder Bed Fusion Followed by HIP

Abstract

Fatigue properties of parts fabricated by laser powder bed fusion, a kind of additive manufacturing, are inferior to those of conventional ways. Defects and inclusions are the causes of low fatigue properties, but the effect is not clarified. Inconel 718 specimens were fabricated by laser powder bed fusion. Cross-sectional observation and fatigue tests were performed. Gas porosity, cracks, and inclusions were observed in cross-section. TiN inclusions were observed in fatigue fracture origins for specimens with hot isostatic pressing. To enhance the fatigue properties of Inconel 718 fabricated by laser powder bed fusion, it is necessary to remove TiN inclusions within the powder.