Influence of sintering conditions on tensile and high cycle fatigue behaviour of powder injection moulded Ti-6Al-4V at ambient and elevated temperatures

Tensile and high cycle fatigue properties of Ti-6Al-4V samples fabricated by powder injection moulding (PIM) are examined at room temperature and elevated temperatures. Standard wrought Ti-6Al-4V material is used for comparison. The tensile and the fatigue strength of samples fabricated by powder injection moulding are found to be significantly lower than conventional wrought material. On the other hand, strength and ductility of metal injection moulded (MIM) samples are high enough to be of large practical interest, in particular if the low processing costs for intricate shapes are taken into account. The inferior properties of the MIM material are caused by considerable remaining porosity, enlarged grain size and increased interstitial content. Prolonged sintering times lead to improved density and strength. At the same time, the room temperature ductility is observed to drop to very low levels, presumably because of additional grain growth.