INVESTIGATION OF BLENDED ELEMENTAL TI-FE SINTERING MECHANISMS USING DIFFERENTIAL SCANNING CALORIMETRY (DSC)

摘要

Iron has been proposed as a densification aid in the sintering of titanium powders and as a possible alloying element for lower cost alternatives to Ti-6Al-4V. While much work has been done looking at iron alloyed with titanium, there is less experience with titanium rich Ti-Fe alloys. In the present study, a combination of differential scanning calorimetry and microstructural analysis was used to investigate the sintering behaviour of titanium alloyed with 2.5wt% relatively coarse (d_(50) = 85 μm) iron. Heating to 1200°C at 20°C/min resulted in coarse porosity due to the formation of eutectic liquid at former iron particle sites. Introducing a soak period below the eutectic melting temperature allowed the iron to diffuse into the titanium such that, after sufficient time, subsequent heating to 1200°C did not result in any liquid formation. However, coarse porosity was still present due to the significantly faster diffusion of iron into titanium leaving behind large voids at former Fe particle sites. Continued work is planned to understand how other variables, such as iron particle size, affect pore formation and the densification of titanium.