A New Mechanism for the Alpha to Omega Martensitic Transformation in Pure Titanium

We propose a new direct mechanism for the pressure driven alpha to omega martensitic transformation in pure titanium. A systematic algorithm enumerates all possible mechanisms whose energy barriers are evaluated. A new, homogeneous mechanism emerges with a barrier at least four times lower than other mechanisms. This mechanism remains favorable in a simple nucleation model.Comment: 4 pages, 4 figure

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

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.Comment: 11 pages, 2 figure