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

Author(s): M. Aspelmeyer, U. Klemradt, L.T. Wood, S.C. Moss

Journal: J. Phys. IV France

Volume: 112

Page(s): 151-157

Year: 2003

DOI Number: 10.1051/jp4:2003854

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.