摘要
Nanometric machining simulations of single-crystal nickel were performed using molecular dynamics.The atomic displacement vector method was applied to study the relationship between defect displacement vectors and the crystal slip system during different deformation stages as well as the displacement trend characteristics of workpiece atoms under different deformations.The arrangement characteristics of atoms in the machining region,relative density of atoms at different machining zones,and proportion of different atoms were investigated in detail.In addition,the atom shunt phenomenon was observed by studying the displacement trend of the atoms adjacent to the machining tool,and a method for determining the location of the shunt point was determined.Moreover,direct evidence of crystal transition caused by temperature was obtained.The effects of machining depth on workpiece damage,surface flatness,and workpiece temperature were investigated.With increasing machining depth,the chip gradually changed from spherical to strip-shaped,the damage depth of workpiece gradually increased,but the atomic arrangement of the machined surface became neater.Simultaneously,the dislocation reaction of subsurface defects was studied,and the rationality of the reaction was analyzed using an energy criterion.Furthermore,the overall temperature of the workpiece increased,but the temperature of the chip part gradually decreased.
Nanometric machining simulations of single-crystal nickel were performed using molecular dynamics. The atomic displacement vector method was applied to study the relationship between defect displacement vectors and the crystal slip system during different deformation stages as well as the displacement trend characteristics of workpiece atoms under different deformations.The arrangement characteristics of atoms in the machining region, relative density of atoms at different machining zones, and proportion of different atoms were investigated in detail. In addition, the atom shunt phenomenon was observed by studying the displacement trend of the atoms adjacent to the machining tool, and a method for determining the location of the shunt point was determined. Moreover, direct evidence of crystal transition caused by temperature was obtained. The effects of machining depth on workpiece damage, surface flatness, and workpiece temperature were investigated. With increasing machining depth, the chip gradually changed from spherical to strip-shaped, the damage depth of workpiece gradually increased, but the atomic arrangement of the machined surface became neater. Simultaneously, the dislocation reaction of subsurface defects was studied,and the rationality of the reaction was analyzed using an energy criterion. Furthermore, the overall temperature of the workpiece increased, but the temperature of the chip part gradually decreased.
基金
supported by the National Natural Science Foundation of China(Grant No.51675254)
