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Highlight Lecture

WEB The Nucleation and Intrinsic Microstructure Evolution of Martensite from {332} ⟨113⟩_β Twin Boundary in β Titanium: First-Principles Calculations

Tuesday (22.09.2020)
10:10 - 10:25 M: Modelling and Simulation 1
Part of:

A clear understanding on the inter-evolution behaviors between {332} ⟨113⟩_β twinning and stress-induced martensite (SIM) α″ in β-Ti alloys is vital for improving its strength and ductility concurrently. As the preliminary step to better understand these complex behaviors, the nucleation and the intrinsic microstructure evolution of martensite α″ from {332} ⟨113⟩_β twin boundary (TB) were investigated in β-Ti at atomic scale using first-principles calculations in this work. We found the α″ precipitation prefers to nucleate and grow at {332} ⟨113⟩_β TB, with the transformation of {332} ⟨113⟩_β TB→{130} ⟨3 ̅10⟩_(α”) TB. During this process, α″ precipitation firstly nucleates at {332} ⟨113⟩_β TB and, subsequently, it grows inwards the grain interiors. This easy transition may stem from the strong crystallographic correspondence between {332} ⟨113⟩_β and {130} ⟨3 ̅10⟩_(α”) TBs, and the region close to the {332} ⟨113⟩_β TB presents the characteristics of intermediate structure between β and α″ phases. Kinetics calculations indicate the α″ phase barrierlessly nucleates at {332} ⟨113⟩_β TB rather than in grain interior, where there is higher critical driving energy. Our calculations provide a unique perspective on the “intrinsic” microstructure evolution of martensite α″ from {332} ⟨113⟩_β TB, which may deepen our understanding on the precipitation of martensite α″ and the inter-evolution behaviors between {332} ⟨113⟩_β twinning and martensite α″ in β-Ti alloys at atomic scale.

Dr. Shangyi Ma
Chinese Academy of Sciences
Additional Authors:
  • Qiu-Jie Chen
    Chinese Academy of Sciences
  • Prof. Dr. Shao-Qing Wang
    Chinese Academy of Sciences