J. Phys. IV France
Volume 112, October 2003
Page(s) 151 - 157

J. Phys. IV France
112 (2003) 151
DOI: 10.1051/jp4:2003854

Growth kinetics of an athermal martensitic transformation by time-resolved optical diffraction from a Ni 63AI 37 (001) surface

M. Aspelmeyer, U. Klemradt, L.T. Wood and S.C. Moss

Physics Department, University of Houston, 4800 Calhoun Rd., Houston, TX 77204-5005, U.S.A.

The vertical and lateral growth process of single martensitic bands on the (001) surface of a Ni 63Al 37 single crystal was investigated using time-resolved diffraction of He-Ne laser light. Our extended kinephotometric setup provided spatial information through an analysis of the Fraunhofer pattern created by diffraction from the surface relief, while temporal resolution was achieved with a fast-response photodiode. On continuous cooling through the martensitic phase transition at a rate of 10 K/min, discontinuous changes in the diffraction pattern occurred on time scales ranging from 100 microseconds up to some tens of milliseconds. Each change in the pattern corresponded to a burst-like upheaval of the relief by a few hundred nanometers. The bands were fully developed within 150-250 ms and reached final heights of about 1.5  $\mu$m.

© EDP Sciences 2003