Dislocation damage and adiabatic shear mechanisms of 7055 aluminum alloy during cutting process

摘要

This paper is intended to examine the dislocation and adiabatic shear mechanisms of 7055 aluminum alloy during cutting process with different cutting speeds. The result indicates that, at low cutting speeds, isometric dislocation cells appear, the dislocation cells are interconnected into dislocation cell blocks, and the dislocation movement is controlled by thermal activation; at high cutting speeds, dislocations mostly come in the form of elongated or not fully closed dislocation cells, and the dislocation movement is controlled by phonon drag; the width of an adiabatic shear band increases with the cutting speed, and low cutting speeds are more likely to result in microcracks. The precipitation-free zones on the grain boundary display a discontinuity under all cutting speeds; distribution and grain size of the precipitates also vary significantly.