Thermal critical stress for plastic deformation

Abstract

At sufficiently high plastic strain rates dissipative heat starts to exert a noticeable influence on the plastic strain process itself. Malygin [1] investigated the influence of this heat on intermittent strain. The method used in [1] to find the instability condition raises doubts since the nonessential stationary stability solution of the problem posed is studied. Petukhov and his colleagues [2] discussed the critical conditions due to the dissipative heat, but the critical stress found increases quadratically with temperature. As the temperature rises at constant stress, the specific intensity of the heat liberation grows, hence, the critical stress should actually diminish. Critical strain conditions are found in this paper by using the formalism of the theory of a thermal explosion [3], and certain singularities in the specimen behavior associated with heat at subcritical conditions are discussed. A detailed description of the behavior of a crystalline specimen under load results in a system of equations difficult so solve, hence, a number of features of the strain which are due to the heat being liberated during the plastic strain are examined in an example of a plate of thickness 2R being deformed by pure shear.