A direct electromagnetic generation of ultrasound techniques is used to study precursor effects in the velocity and attenuation in Nickel-Aluminum alloys near the martensitic phase transformation temperature. This technique probes not only the bulk but also the surface of the materials and will yield valuable information about both the interaction of phonons and the strain fields associated with the defects which cause the transformation. The variation of the elastic constants with hydrostatic and uniaxial pressure will e measured in order to determine the conditions for lattice stability in these alloys. Additional studies with collaborators will employ neutron diffraction work to further characterize the structure of single crystals used in the research project.
