Strain transfer and inhomogeneous deformation in passivated thin films with mixed texture

Thin face-centered cubic metal films on substrates often have mixed (1 1 1)/(1 0 0) fiber texture. These orientations have very different elastic constants, both in and normal to the film plane, leading to significant stress inhomogeneities. Strain transfer between the two orientations leads to complex stress/strain states, hindering interpretations of plastic deformation behaviors such as strain hardening and anelasticity. In this work, we present models to calculate the three-dimensional plastic strains from the three-dimensional elastic strains, and the dislocation densities from the three-dimensional plastic strains, within each texture component of a passivated mixed (1 1 1)/(1 0 0) fiber texture film during biaxial loading. These models are applied to elastic strain data obtained using X-ray diffraction during thermal cycling of thin Cu films. A measure of the strain transfer is obtained and the plastic behavior, both strain hardening and anelastic recovery, is shown to be very different in the two texture components.