hcp → ω phase transition mechanisms in shocked zirconium: A machine learning based atomic simulation study

Hongxiang Zong, Yufei Luo, Xiangdong Ding, Turab Lookman, Graeme J. Ackland

Research output: Contribution to journalArticlepeer-review

Abstract

There has been much controversy over the behavior of zirconium under shock strong enough to cause the pressure-induced hcp → ω phase transformation. Due to the short time- and length scales involved, direct measurements of the microstructure are extremely challenging. We have performed molecular dynamics simulations to investigate this issue, with Zr described by a machine-learned interatomic potential. Two different orientation relationships (ORs) between the hcp and ω phases are observed under shock driven conditions. Unlike the case with Ti that is in the same group, the ORs between the hcp and ω phases show less anisotropic phase transition sensitivity and in most cases follow the Silcock relationship with(0001)α||(12¯10)ω. Furthermore, we find that the α→ ω transformation in shocked Zr occurs via an intermediate metastable bcc structure during the loading process, whereas no such intermediate is found during the reverse ω→α transition when the shock releases.

Original languageEnglish
Pages (from-to)126-135
Number of pages10
JournalActa Materialia
Volume162
Early online date3 Oct 2018
DOIs
Publication statusPublished - 1 Jan 2019

Keywords

  • Orientation relationship
  • Phase transition
  • Shock compression
  • Zirconium

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