Creep and high temperature fatigue performance of as build selective laser melted Ti-based 6Al-4V titanium alloy

Abstract

The present work focuses on the room and high temperature low-cycle fatigue and creep testing of Ti-6Al-4V manufactured by selective laser melting (SLM) or laser-based powder bed fusion process (LBPF). The fatigue specimens were tested in a strain control mode with the as-built and machined surfaces, evaluating the influence of the surface roughness on the fatigue performance. This helps in understanding the potential negative influence of a surface defect/roughness on the fatigue performance of the complex components produced by SLM (in as-built state), where surface machining may not be possible due to geometrical constraints. The fatigue fractures at room and high temperature were investigated with the help of a scanning electron microscope. The creep tests were performed at three different temperatures with as-built SLM samples, demonstrating an equivalent or better performance when compared to their counterparts produced by hot-forging.