Characteristics of Ti6Al4V Powders Recycled from Turnings via the HDH Technique

The objective of this research is for Ti6Al4V alloy turnings, generated during the machining of implants, to produce powders for the fabrication of Ti base coating via the cold spray method. To decrease the cost of powder production and increase the recycling rate of the turnings, the hydrogenation-dehydrogenation (HDH) process has been utilized. The HDH process consists of the following sequence: surface conditioning of the turnings, hydrogenation, ball milling (for powder production), and dehydrogenation. Afterward, the properties of the recycled powder were analyzed via phase, chemical, and morphological examinations and size and flowability measurements. The usability of the powder in additive manufacturing applications has been evaluated by examining the characteristics of the deposit produced from this powder by the cold spray method. In short, promising results were obtained regarding the potential of recycled powders in additive manufacturing after minor adjustments in the HDH process. This study used turnings produced while manufacturing Ti6Al4V–ELI (0.20 wt. % of oxygen) implants as scrap. The flow chart for Ti6Al4V powder production starts with an etching process to clean and activate the surface of the turnings. The turnings were then hydrogenated to form a brittle titanium hydrate for easy milling down to a size of less than 100 μm. Then powders of Ti6Al4V were dehydrogenated as a final step. The produced powder is characterized at the end to evaluate the product's usability for different targets. Additionally, the deposition performance of the recycled powder was analyzed by low-pressure cold spray equipment. Ti6Al4V alloy (Ti, six wt. % Al, four wt. % V) is α + β phase titanium alloy, which occupies about 50% of the total titanium market. It is commonly used in aerospace, automotive, and medical industries due to its high strength/weight ratio, corrosion resistance, biocompatibility, and low thermal expansion characteristics. Although Ti6Al4V alloy is a high-cost material, it loses about 70–80% as scrap while manufacturing engineering components. Due to the high oxygen affinity, recovery of titanium-based scraps by re-melting is difficult and costly. Furthermore, re-melting may cause an imbalance in the alloy co position. From this point of view, recovery of titanium scraps in the form of powder by following the powder metallurgy route can be attractive, especially for the recently-growing additive manufacturing market (such as 3D printing and cold-spray applications, etc.). Thus, powder metallurgy of Ti6Al4V alloy can be an alternative method to use powder as the starting material or recycle the new scrap from semi-fabrication and manufacturing operations as the powder with improved purity. If you are looking for high quality, high purity and cost-effective Ti6Al4V Powders, or if you require the latest price of Ti6Al4V Powders, please feel free to email contact mis-asia.