Cost-affordable Ti-6Al-4V for additive manufacturing: Powder modification, compositional modulation and laser in-situ alloying

Ti-6Al-4V is the single most important Ti alloy, accounting for use in almost 60% of all the applications of Ti materials. Additive manufacturing (AM) offers design freedom with regard to Ti-6Al-4V for creation of highquality, customized products. However, the large-scale development of this technology is constrained by the high raw material costs. In this study, a method based on ball milling powder modification was proposed to convert low cost, non-spherical hydrogenated-dehydrogenated Ti (HDH-Ti) powder into spherical, printable Ti powder. Following mechanical mixing, the ball-milled HDH-Ti powder was further blended with elemental powders of aluminum and vanadium to develop low-cost HDH Ti-6Al-4V. Simultaneously, the issue pertaining to high oxygen associated with HDH Ti-6Al-4V was addressed via introduction of yttrium. A cost-affordable, high-performance AM Ti-6Al-4V alloy was finally developed via laser-based powder bed fusion of metals (PBF-LB/M) after printing parameter optimization and heat treatment. The AM-prepared Ti-6Al-4V demonstrated a relative density of 99.3%, an ultimate tensile strength of similar to 1083 MPa, and an elongation of 9%, comparable to those obtained using costly pre-alloyed powders. Further, numerical simulation and detailed microstructural characterization were performed to reveal the underlying mechanism. Powder modification, compositional modulation, and laser in-situ alloying were the three essential techniques used as part of this approach for optimizing the mechanical properties of the Ti-6Al-4V alloy. Overall, this method demonstrates excellent potential in terms of mitigating the high cost. Moreover, it may further promote research on AM of a variety of Ti alloys besides Ti-6Al-4V.

Automated summary

A method using ball milling powder modification was proposed to convert low-cost HDH-Ti powder into printable Ti powder, leading to the development of a cost-affordable, high-performance AM Ti-6Al-4V alloy. Key techniques for optimizing the mechanical properties of the alloy included powder modification, compositional modulation, and laser in-situ alloying.