Powder Technology, Vol.355, 688-699, 2019
Optimizing hydride-dehydride Ti-6Al-4V feedstock composition for titanium powder injection moulding
Titanium is used in biomedical applications because it is bio-compatible, has high specific strength and high resistance to corrosion. Powder injection moulding (PIM) produces near-net shaped intricate parts, minimizes secondary operations and makes titanium products more cost effective. Feedstocks with 50-65 vol% powder content were manufactured from commercially available hydride-dehydride titanium alloy powder (HDH Ti-6Al-4V; d(10) = 12.8, d(50) = 51.8 and d(90) = 117.7 mu m) and polyvinyl butyral (PVB) based binder. The effect of powder content on mixing torque, feedstock density and viscosity were investigated. Critical powder loadings (CPL) were determined from feedstock density, mixing torque, and viscosity analyses. A new rheological parameter is proposed for predicting CPL based on feedstock flow behaviour. The CPL increased with polyethylene glycol (PEG) content in the binder system. Optimal powder content for HDH Ti-6Al-4V powder was comparable to those reported using small, spherical GA Ti-6Al-4V powder. The HDH Ti-6Al-4V feedstocks exhibited the lowest distribution slope parameter among the published work suggesting it is a cost-effective material for manufacturing parts for biomedical applications. (C) 2019 Elsevier B.V. All rights reserved.
Keywords:Powder injection moulding (PIM);Rheological properties;Critical powder loading;Distribution slope parameter;Feedstock density;Mixing torque