Sandipan Sen, M.Sc.

Curriculum Vitae (CV)

Research Focus

• Study of solute diffusion and self-diffusion in Hexagonal Close Packed (HCP) AlHfScTiZr High entropy alloys
  Majority of studies conducted on high entropy alloys has been focussed on FC systems. Most of the HCP HEAs have been formed using rare-earth elements like CoFeReRu and GdHoLaTbY. Rogal et al. processed a High entropy alloy without using rare earth elements. These alloys are Al x Scb>25 -xHf 25 Ti 25 Zr 25 at.% HEA where x =5 and 15. The Al 15 Sc 10 Hf 25 Ti 25 Zr 25 exhibits an order; disorder transition from a disordered HCP phase at high temperatures to a DO 19 structure below 1203 K . Reducing the Al content to form the Al 5 Sc 20 Hf 25 Ti 25 Zr 25 HEA leads to the disappearance of this order-disorder transformation. In this study, radiotracer diffusion is used to investigate the various diffusion mechanisms that are at play in these HCP HEA systems. The radioisotope 57 Co is selected to investigate the viability of ultra-fast diffusion observed in α-Ti , by conducting diffusion studies systematically on equiatomic binary (HfZr) and ternary (HfTiZr) to quinary Al 5 Sc 20 Hf 25 Ti 25 Zr 25 at.% and Al 15 Sc 10 Hf 25 Ti 25 Zr 25 at.% high-entropy alloys. The findings have already been published . Self-Diffusion of Zr and Ti is also studies in the framework on this study to understand the mechanisms governing the diffusion process in these systems. These diffusion studies will also be used to probe the ordered DO19 phase in the Al 15 Sc 10 Hf 25 Ti 25 Zr 25 alloys. It is to be noted that due to the anisotropy if the HCP crystal structure, the diffusion is also anisotropic. This anisotropy is addressed in the polycrystalline by combining texture studies with diffusion as diffusion is faster along some orientations and slower along others

Publications