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 to 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 MIMtechnique. 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.

Powder Metallurgy Strategies to Improve Properties and Processing of Titanium Alloys: A Review

“…A grain size refinement could also be obtained by blending RE elements with titanium alloys. However, higher amounts of RE elements lead to high porosity (Figure ), and, as a consequence, strength reduction occurs . Moreover, the size of the formed RE oxide particles may impede densification, and the mechanical properties could be affected in a negative way.…”

Metal injection moulding of titanium and titanium alloys: Challenges and recent development

“…While Ti64 is extensively used in the aerospace industry, the high quality standards required for application of any component in aerospace, means the MIM process faces significant hurdles before it can be accepted by this industry. Nonetheless, research has demonstrated that it is possible for the MIM process to manufacture Ti64 components with superior mechanical properties close to the ASTM standard range [5,43,51,100,101] especially by small addition of other elements such as B [43,45], C [71], Gd [58] and TiC [81]. However, most research work on MIM of Ti64 alloy has been specifically designed for biomedical applications [43,83,102] rather than other applications such as aerospace.…”

The effect of zirconium addition on sintering behaviour, microstructure and creep resistance of the powder metallurgy processed alloy Ti–45Al–5Nb–0.2B–0.2C

“…It assumes the values of 1 for a circle and 0 in the case of a line. This method has already been successfully applied to analyse other powder metallurgy processed materials [34].…”