OBSERVATIONS OF THE EFFECT OF AN APPLIED STRESS ON THE MORPHOLOGY OF DISCONTINUOUS PRECIPITATION IN A CU-CD ALLOY

The influence of an applied tensile stress on the morphology and growth rate of the discontinuous precipitation product in a Cu-3.8wt%Cd alloy was first reported by Sulonen. In this contribution, we investigate and further quantify a number of factors associated with the role of applied stress in this alloy, including absolute and relative growth rates of interfaces with normals parallel to and perpendicular to the tensile axis, and the morphological stability of discontinuous precipitation front as a function of the applied stress. Once morphological instability has occurred, the amplitude and wavelength of the protuberences formed depends on the value of the applied stress, and on the angle between the average interface normal and the tensile axis. It is suggested that the process is best viewed as one of transformation-assisted viscoelastic deformation.