Fracture mechanics of metallic plates under the conditions of high-temperature creep

We propose a mathematical model for the analysis of subcritical growth of high-temperature creep cracks in metallic plates. The model is based on the first law of thermodynamics on the energy balance and the balance of rates of changes in the energies in a metallic plate containing a macrocrack stretched by a long-term static load under the action of a high-temperature field, which creates favorable conditions for steady-state creep in the process zone near the crack tip. We deduce an equation for the description of the process of propagation of high-temperature creep cracks. This equation equipped with the corresponding initial and final conditions is regarded as a mathematical model for the evaluation of the period of subcritical growth of hightemperature creep cracks in metallic plates. The validity of the model is experimentally checked.