Surface stress problem in heterogeneous mechanochemical reactions

The present situation with the surface stress and chemical potential definitions for a non-hydrostatically stressed solid is reviewed. It is demonstrated that the definition of surface stress in a solid based on R. Shuttleworth's paper (1950) and widely used for many years is erroneous. It should be substituted with the definition of stress tensor generally accepted in the theory of elasticity. Different definitions of the deformation-induced change of the chemical potential in solids (starting from Gibbs) as a driving force of mechanochemical reactions are discussed and compared with experimental data. Perhaps, the reason of contradictory results is that the possibilities of continuum mechanics are exhausted here, and further development requires an atomistic approach with a discrete model of a solid including electron density distribution in chemical bonds.