2011/11/26 by Arya Paul, Paul, Arya, Surajit Sengupta +3
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Metallic Glasses and Amorphous Alloys #Microstructure and mechanical properties #Shape Memory Alloy Transformations #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.1111.6130
17 pages, 6 figures
arxiv created 2011/11/26 · openalex publication_date 2011/11/26 · arxiv updated 2011/11/29 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
We describe the microstructure, shape and dynamics of growth of a droplet of martensite nucleating in a parent austenite during a solid-solid transformation, using a Landau theory written in terms of conventional affine, elastic deformations and \em non-affine degrees of freedom. Non-affineness, ϕ, serves as a source of strain incompatibility and screens long-ranged elastic interactions. It is produced wherever the local stress exceeds a threshold and anneals diffusively thereafter. A description in terms of ϕ is inevitable when the separation between defect pairs, possibly generated during the course of the transformation, is small. Using a variational calculation, we find three types of stable solutions (\hv I, \hv II and \hv III) for the structure of the product droplet depending on the scaled mobilities of ϕ parallel and perpendicular to the parent-product interface and the stress threshold. In \hv I, ϕ is vanishingly small, \hv II involves large ϕ localized in regions of high stress within the parent-product interface and \hv III where ϕ completely wets the parent-product interface. While width l and size W of the twins follows l∝√(W) in solution \hv I, this relation does not hold for \hv II or \hv III. We obtain a dynamical phase diagram featuring these solutions and argue that they represent specific microstructures such as twinned or dislocated martensites.