Microstructures and Mechanical Properties of Ti600 Alloy Manufactured by Selective Laser Melting

The influence of the energy density on the microstructures,phase-structures and mechanical properties of Ti600 Ti-alloy,an advanced internal combustion engine material manufactured by selective laser melting(SLM) of Ti600 powder,was investigated with X-ray diffraction,scanning electron microscopy,and conventional mechanical probes.The preliminary results show that the energy density had a major impact.To be specific,selective laser melting always produced white α'-phased grains.As the energy density decreased to about 60 J/mm³,formation of quite a few β-phase appeared and more dimple fractures existed at the tearing ridges of the Ti-alloy with better toughness; to 52 J/mm³,only tensile strength significantly increased and in-situ decomposition of β-phase martensite induced much precipitation of α'-phase,accompanied by formation of(α'+β) phased needles,~0.6 μm in diameter; to~ 44 J/mm³,β-phase content slightly decreased.