Abstract
TIMETAL® 54M (Ti-54M) with a nominal chemical composition of Ti–5Al–4V–0.6Mo–0.5Fe is a relatively new (α + β) Ti alloy. This alloy has been developed to offer better machinability and forgeability in comparison to the well-known Ti-6Al-4V. However, the knowledge about phase transformation behaviour of Ti-54M during continuous heating and cooling is still insufficient. Hence, the present study is focused on this topic. In order to accomplish this purpose, high energy synchrotron X-ray diffraction (HE-XRD) together with a dilatometer setup was used for in situ measurements to trace the phase evolution with a reasonable time resolution. The phase transformation behaviour is discussed based on the change in the HE-XRD diffraction patterns, resulting in a continuous-cooling-transformation (CCT) diagram, as well as by means of microstructure and microhardness results. In addition, the results are compared with the published Ti-6Al-4V data. It was found that the temperature range of the β→α phase transformation of Ti-54M during cooling at higher rates is larger than that of Ti-6Al-4V, which results in different CCT diagrams.
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