Research on the Improvement of Shape-Memory and Magnetostrictive Materials
Abstract
The goals of this research are to give predictive, quantitative models that can be used to improve shape-memory and magnetostrictive materials, and that can guide the development of new materials. A new theory of martensite and a new theory of magnetostriction were found, both of which predict accurately observed domain structures in these alloys. The principal findings based on these theories are (1) the importance of the precise values of the lattice parameters in determining the microstructure, and therefore the behavior of these materials; (2) the presence of the growth twins in Tb(x)Dy(1-x)Fe2, the material with the largest known magnetostriction, do not decrease the magnetostrictive strain in this alloy, as was formerly thought; (3) thermoelastic theory gives a mechanism for increased strain-rate dependence in uniaxial tension experiments on TiNi. A unique experimental facility was built for fundamental experimental studies on stress and magnetic field-induced phase transformation. Shape-memory materials, Magnetostriction, Martensite, Phase transformations, Stress-induced transformation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 13, 1993
- Accession Number
- ADA275397
Entities
People
- Richard D. James
Organizations
- University of Minnesota