Pin-Type Bearing Strength and Fracture Behaviour of Ductile LPBF Ti-6Al-4V ELI Produced with Extensively Reused Powder

Abstract

Metal additive manufacturing is a manufacturing technology that is being investigated for critical industrial applications in industries such as aerospace, nuclear, and medical. A degree of uncertainty remains around these technologies largely due to process and material repeatability, production controls, and a lack of application-specific material data. This research aimed to investigate the effects of extensively reused (175 reuse cycles) Ti-6Al-4V ELI powder feedstock and build orientation on the produced material. Material chemistry, metallography, pin-type bearing strength, and tensile properties were characterized at different build locations and principal orientations. The literature on pin-type bearing strength for both traditionally and additively manufactured material is lacking. Such information is of value for the design of bolted structural joints and fixtures. The results suggest that although extensively reused powder feedstock does experience drift in material properties due to the reuse process, it can still fulfil feedstock material specification requirements. Furthermore, this powder is capable of producing material that meets produced material specification requirements, exhibits minimal orthotropy in mechanical properties, and has ultimate bearing strength that exceeds Ti-6Al-4V grade 5 wrought material allowables. This research provides valuable information for designing structural joints and contributes to the further industrialization of laser powder bed fusion for critical applications.