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Article
Shape-Memory Transformations of NiTi: Minimum-Energy Pathways between Austenite, Martensites, and Kinetically Limited Intermediate States
Physical Review Letters
  • Nikolai A. Zarkevich, Ames Laboratory
  • Duane D. Johnson, Iowa State University
Document Type
Article
Publication Version
Published Version
Publication Date
12-24-2014
DOI
10.1103/PhysRevLett.113.265701
Abstract

NiTi is the most used shape-memory alloy; nonetheless, a lack of understanding remains regarding the associated structures and transitions, including their barriers. Using a generalized solid-state nudged elastic band method implemented via density-functional theory, we detail the structural transformations in NiTi relevant to shape memory: those between a body-centered orthorhombic (bco) ground state and a newly identified stable austenite (“glassy” B2-like) structure, including energy barriers (hysteresis) and intermediate structures (observed as a kinetically limited Rphase), and between martensite variants (bco orientations). All results are in good agreement with available experiment. We contrast the austenite results to those from the often-assumed, but unstable B2. These high- and low-temperature structures and structural transformations provide much needed atomic-scale detail for transitions responsible for NiTi shape-memory effects.

Comments

This article is from Physical Review Letters 113 (2014): 265701, doi:10.1103/PhysRevLett.113.265701. Posted with permission.

Copyright Owner
American Physical Society
Language
en
Date Available
2015-03-04
File Format
application/pdf
Citation Information
Nikolai A. Zarkevich and Duane D. Johnson. "Shape-Memory Transformations of NiTi: Minimum-Energy Pathways between Austenite, Martensites, and Kinetically Limited Intermediate States" Physical Review Letters Vol. 113 (2014) p. 265701
Available at: http://works.bepress.com/nikolai_zarkevich/10/