Strained Ion Tracks in Amorphous Solids: Origin of Plastic Deformation

Track formation in amorphous solids is treated in terms of viscoelastic shear stress relaxation in thermal spike regions which is followed by the freezing-in of the associated strain increment. The resulting strained tracks are considered to be the mesoscopic defects responsible for anisotropic creep and growth. A recently presented approximate quantitative approach to the problem is reviewed. In addition, a new set of constitutive equations describing the viscous flow in thermal spike regions is suggested and general solutions are discussed.