Ryan S. Elliott
Assistant Professor
Research
Martensitic solid-to-solid phase transformations
Martensitic solid-to-solid phase transformations are responsible for the remarkable properties of shape memory alloys (SMAs) such as NiTi. This project aims to understand the existence of temperature-induced and stress-induced transformations in SMAs by studying an atomistic model using bifurcation and path-following techniques. These techniques provide a wealth of detailed information that helps to explain the presence of these transformations and could eventually be used to design new SMAs that have dramatically improved properties.
The graph displays the uniaxial stress-strain behavior of the atomistic SMA model. This bifurcation diagram shows the existence of multiple stable phases (solid line segments) of the material and how these stable phases are connected to each other through unstable segments (broken lines) of the stress-strain paths.The unit cells of the stable B2, B33, B11, and C2/m crystal structures are illustrated and the corresponding stable stress-strain path segments are labeled in the graph.
These results indicate the existence of Martensitic transformation in this material and are leading to a better understand of the amazing shape changing behavior of materials such as NiTi, CuAlNi, and AuCd.
Last Modified: Wednesday, 02-Jan-2008 05:59:04 CST