Early stages of atomic mixing and chemical disordering processes in solid phases under shear: Numerical simulations

Numerical simulations have been used to study atomic mixing and chemical disordering processes in solid solutions and equilibrium compounds with weak and negative enthalpies of mixing, respectively. Calculations were carried out at different shearing rates and temperatures. The mechanical forces induced a gradual distortion of the atomic coordination shells, involving initially the central region of the simulated systems and then extending outwards. This determined the formation of a layer of atomic planes with perturbed structure the thickness of which changed with time according to the power law generally pertaining to thermal diffusion. The rate of the perturbed layer thickness increase, strongly dependent on the shearing rate, is similar for all the systems investigated despite their different thermodynamic properties.