Abstract
The problem on strain-induced chemical reaction (SICR) and structural changes (SCs) in a thin layer inside the shear band is formulated and solved for large strains. It is analytically demonstrated that intense plastic deformation can accelerate chemical reactions. The phenomenon of reaction-induced plasticity (RIP), similar to transformation-induced plasticity at phase transitions is derived and modelled. A criterion for athermal SICR is derived and distinctive points of the approach proposed at zero shear stresses and classical chemical thermodynamics are analysed. Two mechanisms are proposed for the experimentally observed positive effect of shear stresses on SC from the low temperature phase to the high temperature phase. The first one is related to the necessity of fulfilment of the yield condition for the transforming material. The second mechanism is connected with the additional heating due to RIP. A kinetic criterion of chemical reaction is formulated. As an example, the SICR in Ti–Si and Nb–Si mixtures is considered. It is shown that the main reason for acceleration of reaction kinetics due to shear stress or strain is related to the increase of effective temperature due to RIP. The increase of driving force due to shear stresses does not affect the kinetics.
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