@article{1e87495ead2f41f4a09bb97eb8f54239,
title = "The influence of Al-based powder additives on the sintering behaviour of Ti–6Al",
author = "J. Lapointe and J. O'Flynn and Plucknett, {K. P.} and Corbin, {S. F.}",
note = "Funding Information: In contrast, the interrupted MA mixtures look markedly different (Fig. 3d–f). At 850 °C, the TiAl MA particles appear intact and only a small amount of localized interaction is visible between the Ti and MA particles at contact points. Since the MA additions do not melt and are already in intermetallic form, there is much less driving force for interaction between the Ti and MA additions compared to the elemental Al additions. This is also supported by the lack of any clear reactions measured in the DSC for the MA mixtures up to this temperature. At 950 and 1050 °C, a bright white intermetallic layer becomes progressively more pronounced between the Ti and MA particles and around the MA particles. As with the BE mixture after Al melting and intermetallic formation, interaction between the MA intermetallics and Ti particles appears to be limited until the Ti transitions to the β phase, where its diffusion rates increase significantly [12], as noted earlier. In contrast to the BE mixtures, however, the intermetallics are not distributed in a thin layer over the Ti particles, but instead concentrated in the MA addition particles. As shown in the homogenization section that follows, this lack of distribution in the MA mixtures results in longer homogenization times.Microscopy was also used to assess the homogeneity of the mixtures after different sintering times. Fig. 7 shows cross sections of the coarse BE and MA mixtures after 0, 15 and 120 min holds at 1200 °C. Note that etching causes Ti-rich regions to appear darker. The coarse MA mixture is clearly inhomogeneous after no hold (0 min), with significant Ti-rich regions visible in the microstructure. After 15 min, isolated Ti-rich regions remain in the coarse MA, while at 120 min the sample appears homogeneous. The coarse BE mixture follows a similar trend, however the level of localized inhomogeneity is less significant at the 0 and 15 min sintering times compared to the coarse MA compact. A few etched, Ti-rich regions remained in the coarse BE samples, even after 120 min, suggesting some long-range inhomogeneity remained in this sample, possibly due to agglomeration of the additions. These results support the observations made from the DSC traces.The authors would like to thank the Natural Sciences and Engineering Research Council of Canada (NSERC) and its Discovery Grant (DG) and Automotive Partnerships Canada (APC) program for their financial support of this research. They would also like to thank Wescast Industries Inc. and Kingston Process Metallurgy Inc. for their financial, in-kind and technical support. Funding Information: The authors would like to thank the Natural Sciences and Engineering Research Council of Canada (NSERC) and its Discovery Grant (DG) and Automotive Partnerships Canada (APC) program for their financial support of this research. They would also like to thank Wescast Industries Inc. and Kingston Process Metallurgy Inc. for their financial, in-kind and technical support. Publisher Copyright: {\textcopyright} 2023 Elsevier B.V.",
year = "2023",
month = mar,
day = "1",
doi = "10.1016/j.matchemphys.2023.127453",
language = "English",
volume = "297",
journal = "Materials Chemistry and Physics",
issn = "0254-0584",
publisher = "Elsevier BV",
}