Effects of lubrication on the powder metallurgy processing of titanium

Abstract

The role of lubrication on the consolidation behaviour of titanium powder, density increase and change in microstructure on subsequent sintering was investigated. HDH titanium powder mixed with 0-2wt% stearic acid or magnesium stearate was cold compacted. It was found that 0.3-0.6wt% of internal lubricant significantly improves the compressibility. However, more than 0.6wt% of lubricant aids the densification in the low-pressure region but limits the maximum density at high pressure. Moreover, 0.3-0.6wt% of lubricant offers a more uniform density distribution to the powder compact, while greater than 0.6wt% of lubricant leads to a segregation of lubricant in the surface region. The shape retention, ejection behaviour, de-lubrication behaviour and sintered properties were also studied in this work.