Titanium alloys are widely used in aerospace, biomedical and automotive industries due to their excellent properties such as a high strength to weight ratio, corrosion resistance and biocompatibility. The conventional processing is energy-intensive and costly due to the melting and refining processes while solid state processing promises alternatives for producing near-net shapes and low cost. Powder processing also takes advantage of early forms of titanium processing routes such as working with initial sponge or using machining wastes in the future. Despite this, few studies have directly compared these powder based processes under consistent processing conditions to clarify how each process influences microstructure and hardness in Ti6Al4V.

 

This study investigated four powder-based techniques: powder consolidated pucks, hot isostatic pressing (HIP), cold spray deposition of powders and cold isostatic pressing (CIP) as a cost-effective process for producing Ti6Al4V with increased densification and hardness. This was carried out using low cost titanium powder produced directly from its ore through two stage powder production process. All samples were vacuum sintered and hot rolled; microstructural characterization, hardness testing and oxygen analysis were conducted to establish the relationship between processing, microstructure and mechanical behavior. Sintering above the beta transus temperature enhanced the densification of all the samples to approximately 98% reducing the porosity across all samples. Subsequent thermomechanical processing at the alpha-beta region further increases densification and refines the alpha-beta structure resulting in improved hardness with samples achieving approximately 474HV0.5 comparable to or exceeding that of wrought Ti6Al4V. Increasing oxygen content also contributed to strengthening via solid solution hardening.

 

These findings show that powder-based processing combined with vacuum sintering and thermomechanical deformation can produce high-density Ti6Al4V with a wrought-like microstructure and hardness, establishing a link between the processing, microstructural changes and mechanical behavior emphasizing the potential of cost-effective powder processing as an alternative to conventional wrought titanium processes.