Smart Materials Between Two and Three Dimensions

Shape-memory alloys involving martensitic transformations, are important as smart materials. Both the transformation nucleation and the sample morphology are unsolved issues relevant for these applications. Of particular note are the softening of certain lattice-vibrational frequencies, the development of a tweed-like microstructure on cooling the material and the role of defects, particularly the sample surface, in the transformation process. This project addresses these issues using model materials in thin-film and bulk-crystal forms. Capacitance dilatometry, optical, electron and scanning-probe microscopies, and x-ray techniques, will unlock an understanding of the physical and metallurgical conditions controlling these transformations.