STRESS DISTRIBUTIONS AND MATERIAL RESPONSE IN THERMAL SPRAYING OF METALLIC AND CERAMIC DEPOSITS

In this paper, a numerical model is presented simulating heat transfer and buildup of differential thermal contraction stresses during thermal spraying. Comparisons are made between prediction and experiment for the substrate/deposit curvatures exhibited during and after spraying of both metallic and ceramic deposits. It is shown that while the basic assumptions of the model seem acceptable, representation of the mechanical response of the materials is important and can be complex. The magnitudes of the stresses are often sufficient to cause plastic flow or other relaxation effects such as microcracking. For the ceramic deposits studied, it was found necessary to employ a simple damage evolution law in which the tensile stiffness of the deposit is progressively reduced, although at a decreasing rate, as straining takes place. Implications for optimization of deposit integrity and strength are briefly mentioned. © 1990 The Minerals, Metals & Material Society.