Anisotropy of elastic aftereffect in FCC metals

The deformation of rolled copper and aluminum sheets has been studied at a constant load in the elastic range. Anisotropy in their elastic aftereffect has been detected. The time-dependent part of the deformation is found to be best described by a power function of time with a fractional exponent. A mathematical model is proposed to describe the elastic aftereffect of a metal using the fractal concepts of deformation. A strictly exponential time dependence is shown to transform into an anomalous dependence when a continuous relaxation-period distribution transforms into a fractal relaxation-period distribution during elastic aftereffect in fcc metals. The exponent of the power dependence of the strain on the time determines the fractal dimension of relaxation during the elastic aftereffect.