Near-Net-Shape Forming of Ti-6Al-4V Alloy by VacuumPlasma Spraying: A New Concept for ManufacturingComplex Shape Structures

Recently, vacuum plasma spray forming (VPSF) has beenidentified as a process capable of manufacturingnear-net-shape components for advanced technologyapplications such as aerospace, defense, and chemicalprocess industries. By optimizing the depositstructure via intelligent control of processparameters and utilizing post-deposition heattreatments, deposit structures with properties betterthan conventionally cast materials and, in somecases, equivalent to wrought materials can beproduced. In this study, VPSF process has beenemployed to form near-net-shape structures of one ofthe most important and widely used titanium alloys,Ti-6Al-4V. Since the quality requirements for sprayedstructural materials are different than those forcoatings, characterization of the standard coatingparameters does not fully address the microstructurerequirements that must be met to assure optimalproperties. The initial powder, as-sprayed structureand splat formation of the alloy during thermal sprayprocess were investigated comprehensively in thisstudy. Three heat treatment cycles were developed toachieve desired physical and mechanical properties ofthe VPS deposited material.