• Structural aspects of alpha-omega transformation in group IV transition metals and alloys

    • Fulltext


        Click here to view fulltext PDF

      Permanent link:

    • Keywords


      Alpha-omega phase transformation; structure; high pressure; orientation relations; transition metals

    • Abstract


      The three most common crystal structures encountered in group IV transition metals Ti, Zr, and Hf and alloys based on them, under different temperature, pressure and alloy concentration conditions, are hcp(α), bcc (β) and simple hexagonal (ω). Although the structural relations of α⇌β andβω transformations are well understood, the same is not true for α→ω phase change, which occurs at high pressures. We have done high pressure experiments on Ti-V alloys, followed by electron diffraction to study this. These patterns from pressure treated foils of alloys Ti95 V5 and Ti91 V9 showed the presence ofβ-phase with fourω variants. Some of them showed the existence of all three phases, α,β andω, with the number of variants given by the lattice correspondence matrix, derived through the orientation relations of α →β andβω. This is a clear evidence that the α →ω transformation proceedsvia theβ-phase. The atomic rearrangements required forαω are found to be much smaller if the path is via theβ-phase, rather than the earlier model of Silcock.

    • Author Affiliations


      Y K Vohra1 S K Sikka1 R Chidambaram1

      1. Neutron Physics Division, Bhabha Atomic Research Centre, Trombay, Bombay - 400 085, India
    • Dates

  • Bulletin of Materials Science | News

    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.