Systematic pathway generation and sorting in martensitic transformations: Titanium alpha to omega

TL;DR

This paper introduces a systematic algorithm for generating and sorting transformation pathways in martensitic phase changes, specifically applied to titanium alpha to omega transition, highlighting the importance of atomistic analysis.

Contribution

The authors develop a new algorithm that efficiently generates and ranks martensitic transformation pathways based on energy barriers, applied to titanium phase transition.

Findings

Seven lowest energy pathways identified with detailed symmetry analysis.

No simple geometric criterion exists for pathway selection, emphasizing atomistic study importance.

Efficient pathway sorting within geometric limits demonstrated.

Abstract

Structural phase transitions are governed by the underlying atomic transformation mechanism; martensitic transformations can be separated into strain and shuffle components. A systematic pathway generation and sorting algorithm is presented and applied to the problem of the titanium alpha to omega transformation under pressure. In this algorithm, all pathways are constructed within a few geometric limits, and efficiently sorted by their energy barriers. The geometry and symmetry details of the seven lowest energy barrier pathways are given. The lack of a single simple geometric criterion for determining the lowest energy pathway shows the necessity of atomistic studies for pathway determination.