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 (beta stabilizing element). Experimental results showed that addition of Mo into the Ti-6Al-4V alloy effectively suppressed the formation of alpha' martensite and increased the fraction of beta phase in the as-SLMed simple cubic structure. At 15 wt.% Mo addition, the martensitic transformation was completely suppressed and full metastable beta 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 x 10(-3) to 18.6 x 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.

Automated summary

The addition of Mo to Ti-6Al-4V alloy can effectively increase the content of beta phase, suppress the formation of martensite, and improve the fracture ductility and energy absorption capacity of the alloy.