Vacuum plasma spraying: A new concept for manufacturing Ti-6Al-4V structures

In this study, near-net-shape formed Ti-6Al-4V alloy was manufactured by vacuum plasma spraying. The microstructure and room-temperature mechanical properties of the as-sprayed and heat-treated specimens were investigated. The sprayed structure consisted of individual lamellae (splats) along with splat boundaries and pores. Phase composition was found to be mainly martensite with less than 10% retained β-Ti. Although the tensile strength of the assprayed structure was close to that of conventionally manufactured material, elongation was as low as 1%. The failure mechanism responsible for the low level of elongation was investigated. To improve the elongation, three heat-treatment cycles were optimized for Ti-6Al-4V near-net-shape formed structures. The elongation and Young's modulus of the structures were successfully improved by all heat-treatment schedules.