Temperature-dependent micro crack healing process

The crack healing process is studied theoretically on the basis of the extended the Thomson-Obreimoff model. The system free-energy F as a function of the crack length l and temperature T is calculated using the self-consistent Einstein model. It is found that with the temperature increase, the energy barrier becomes lower and even disappears at the "healing" temperature T = T-h. It is demonstrated that the crack-lattice trapping in the Obreimoff model is controlled by the free-energy barrier height Delta F(T). The latter exhibits the universal power-law behavior. On the basis of the results obtained, the crack healing time is evaluated.