Altering the Stability of Surface Plastic Flow via Mechanochemical Effects

Cutting and surface deformation of metals typically involve large strains and one of four distinct modes of plastic flow. The conditions under which each of these modes occur, and their relative stabilities, have been the subject of much debate. Using controlled deformation experiments and high-resolution $i\phantom{\rule{0}{0ex}}n$ $s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ observations, the authors reveal a fundamental connection between the ambient chemical environment and the stability of flow modes. Huge gains in surface quality and reduction of deformation forces can be attained by controlling the chemical interaction with the flow, suggesting routes to enhanced metal processing via suitably tailored mechanochemical interactions.