Investigations on Ti–6Al–4V with gadolinium addition fabricated by metal injection moulding

Abstract

This study presents the results of investigations on Ti–6Al–4V alloyed with 1–5 wt.% gadolinium. The Ti–6Al–4V + Gd samples are fabricated by metal injection moulding (MIM) using Ti–6Al–4V and elemental gadolinium powder. In previous investigations, it is shown that TiB precipitates in Ti–6Al–4V fabricated by MIM result in a microstructure refinement, while the removal of oxygen improves the ductility. Thus, rare earth elements could possibly combine both effects in one, by reacting with oxygen from the titanium matrix and by forming small oxides leading to grain refinement. Because there are actually no investigations concerning Ti–6Al–4V alloyed with gadolinium, this study mainly gives a first overview to show how the microstructure and mechanical features of Ti–6Al–4V change. In order to provide this overview, this study shows that it is possible to prepare a reasonable homogeneous powder metallurgical Ti–6Al–4V alloy with Gd additions by using the MIM-technique. Adding Gd to Ti–6Al–4V alloy powder and processing the blend by MIM leads to significant grain refinement and a slight change in pore size and shape. However, strength and ductility are reduced by the addition of Gd.