Solid-to-solid martensitic phase transformations are responsible for the remarkable behavior of shape memory alloys. There is currently a need for shape memory alloys with improved corrosion, fatigue, and other properties. The development of new accurate models of martensitic phase transformations based on the material's atomic composition and crystal structure would lead to the ability to computationally discover new improved shape memory alloys. This paper explores the Effective Interaction Potential method for modeling the material behavior of shape memory alloys. In particular, an extensive parameter study of the Morse pair potential model of the stress-free B2 cubic crystal is performed. Results for the stability, potential energy, current unit cell volume, instantaneous bulk modulus, and the two instantaneous cubic shear moduli are presented and discussed. It is found that an Effective Interaction Potential model based on the Morse potential is appropriate for modeling transformations between the B2 cubic structure and the B19 orthorhombic structure, but is not likely to be capable of simulating the B2 cubic to B19 monoclinic transformation found in the popular shape memory alloy NiTi. In fact, this conclusion may be extended to all types of pair interaction potential models.
Bibliographical noteFunding Information:
This work has been supported by the National Science Foundation CAREER Grant CMMI-0746628 (Dr. Shih-Chi Liu, Program Director); by The University of Minnesota Grant-In-Aid of Research, Artistry and Scholarship Program (GIA); and by The University of Minnesota Supercomputing Institute.
Copyright 2008 Elsevier B.V., All rights reserved.
- B2 crystal
- Martensitic precursor behavior
- Morse potential
- Shape memory alloys