A new mechanism of plastic flow

Abstract When ductile materials are tested in simple shear, with moderate amounts of compressive stress on the shear plane, what appears to be negative strain hardening occurs at relatively large strains. These results are in apparent contradiction to the commonly held views that metals strain harden without saturation to the highest values of strain and that compressive stress on the shear plane does not influence flow stress. A new mechanism of plastic flow is presented that involves the formation and rewelding or microcracks of limited extent on shear surfaces. Possible applications of the new theory to metal cutting and geological events are briefly discussed.