PLASTIC-DEFORMATION ANALYSIS IN MACHINING OF INCONEL-718 NICKEL-BASE SUPERALLOY USING BOTH EXPERIMENTAL AND NUMERICAL-METHODS

Surface region plastic deformation of Inconel-718 nickel-base superalloy workpieces was evaluated when machined under orthogonal cutting conditions at various cutting speeds. Plastic deformation analysis was accomplished by determining the residual stress and plastic strain distributions in the surface region. The residual stresses were tensile and maximum near the surface and decreased in magnitude with an increase in depth beneath the machined surface. Similarly, the plastic strains were maximum near the surface and decreased with an increase in depth beneath the machined surface. In addition, a finite element simulation of orthogonal machining was carried out for predicting the residual stress and plastic strain distribution. In general, the trend of the curves predicted by the finite element model was similar to those found experimentally.