The Effect of Sputtering on Stress Distributions in Plasma-Facing Components

Stress histories in bonded duplex structures subject to creep and surface erosion are explored using the finite element method. Erosion is simulated by reducing the elastic modulus of the appropriate elements by several orders of magnitude. In the absence of creep, erosion of a graphite tile on a copper substrate is found to have no effect on the interface stresses in the structure. Stress relaxation in the copper substrate reduces the differences in the stiffnesses of the two materials, leading to enhanced erosion effects in the presence of creep. Erosion thus is found to increase the stress relaxation rate.