Mechanical performance of simple cubic architected titanium alloys fabricated via selective laser melting

Simple cubic architected titanium alloys with 72.7% porosity were additively manufactured via selective laser melting (SLM). Their mechanical performance was closely related to the alloy composition that was controlled through in-situ alloying of Ti-6Al-4V with Mo (β stabilizing element). Experimental results showed that addition of Mo into the Ti-6Al-4V alloy effectively suppressed the formation of αʹ martensite and increased the fraction of β phase in the as-SLMed simple cubic structure. At 15 wt.% Mo addition, the martensitic transformation was completely suppressed and full metastable β phase was obtained in the alloy. As a result, the first compressive fracture strain of the SLMed architected alloy increased from 2.82% (without Mo addition) to 7.24%, the elastic modulus decreased from 12.6 ± 3.3 GPa to 6.7 ± 0.6 GPa, and yield strength to elastic modulus ratio was accordingly increased from 12.9 × 10⁻³ to 18.6 × 10⁻³. In addition, the architected simple cubic structure also demonstrated a controllable plateau stress and high energy-absorbing capacity. As Mo addition increased from 0 wt.% to 15 wt.%, the cumulative energy absorption to the densification strain significantly increased from 31.9 mJ m⁻³ to 47.7 mJ m⁻³. Hence, the simple cubic architected titanium alloys will have strong potential to be used to fabricate vibration damping devices and biomedical implants.