In situ synchrotron X-ray diffraction study of continuous cooling transformations of TIMETAL 54M

[摘要] TIMETAL (R) 54M (Ti-54M) with a nominal chemical composition of Ti-5Al-4V-0.6Mo-0.5Fe is a relatively new (alpha + beta) 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 Ti54M 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-6Al4V data. It was found that the temperature range of the beta ->alpha phase transformation of Ti-54M during cooling at higher rates is larger than that of Ti-6Al-4V, which results in different CCT diagrams. (c) 2021 Elsevier B.V. All rights reserved.

[发布日期] 2021-11-10

[关键词] TIMETAL 54M;Phase transformation;CCT diagram;X-ray diffraction;Dilatometer