Deformation mechanisms and constitutive modeling for silicon nitride undergoing laser-assisted machining

Material deformation behavior has been studied for silicon nitride containing 10 wt% of YSiAlON glass under laser-assisted machining (LAM). Material removal mechanisms were inferred from scanning electron microscopy observations of the chips, and the shear zone stress was determined using three-dimensional machining theory with a new approach to determining shear angles for segmented chips formed in LAM. The effects of operating conditions on the shear zone stress were determined from an experimental parametric study, and the results were used to develop a constitutive equation for the deformation process. (C) 2000 Elsevier Science Ltd. All rights reserved.