HOW STRAINS AND STRAIN RATES ARE ACCOMMODATED BY DISLOCATIONS AND TWINS DURING CHIP FORMATION BY MACHINING

摘要

Chip formation by machining is a high-rate, severe plastic deformation process characterized by unique micromechanics associated with the accommodation of the large strains at high strain rates. This accommodation involves interplay of dislocation and twinning mechanisms, each of which is dominant in distinct deformation regimes as a function of the material crystallography. We present some fundamental experimental characterization of these strain accommodation phenomena by coupling strain and strain-rate measurements to the elucidation of the microstructure in the severely deformed chips.