Novel mixed-mode phase transition involving a composition-dependent displacive component.

Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, USA.
Physical Review Letters (Impact Factor: 7.73). 06/2011; 106(24):245701. DOI: 10.1103/PhysRevLett.106.245701
Source: PubMed

ABSTRACT Solid-solid displacive, structural phase transformations typically undergo a discrete structural change from a parent to a product phase. Coupling electron microscopy, three-dimensional atom probe, and first-principles computations, we present the first direct evidence of a novel mechanism for a coupled diffusional-displacive transformation in titanium-molybdenum alloys wherein the displacive component in the product phase changes continuously with changing composition. These results have implications for other transformations and cannot be explained by conventional theories.