Post-sintering heat treatments for porous coated Ti-6A1-4V alloy.

Previous studies have shown that the application of a porous Ti-6A1-4V alloy coating results in a substantial decrease in the substrate material fatigue properties. This phenomenon is due to both a microstructural change from the equiaxed alpha-beta microstructure to a lamellar structure and a notch effect created by the porous coating. The lamellar microstructure has been shown to exhibit the worst fatigue properties of the most common structures obtained in Ti-6A1-4V alloy. This study examined various post-sintering heat treatments which would alter the material microstructure and possibly result in improved fatigue performance. The heat treatments examined produced alternate microstructures to the lamellar structure and some approached the totally transformed acicular alpha structure. The acicular alpha structure has been shown to exhibit the best fatigue properties for Ti-6A1-4V alloy in the notched condition.