title: The evolution of machining-induced surface of single-crystal FCC copper via nanoindentation.
abstract: The physical properties of the machining-induced new surface depend on the performance of the initial defect surface and deformed layer in the subsurface of the bulk material. In this paper, three-dimensional molecular dynamics simulations of nanoindentation are preformed on the single-point diamond turning surface of single-crystal copper comparing with that of pristine single-crystal face-centered cubic copper. The simulation results indicate that the nucleation of dislocations in the nanoindentation test on the machining-induced surface and pristine single-crystal copper is different. The dislocation embryos are gradually developed from the sites of homogeneous random nucleation around the indenter in the pristine single-crystal specimen, while the dislocation embryos derived from the vacancy-related defects are distributed in the damage layer of the subsurface beneath the machining-induced surface. The results show that the hardness of the machining-induced surface is softer than that of pristine single-crystal copper. Then, the nanocutting simulations are performed along different crystal orientations on the same crystal surface. It is shown that the crystal orientation directly influences the dislocation formation and distribution of the machining-induced surface. The crystal orientation of nanocutting is further verified to affect both residual defect generations and their propagation directions which are important in assessing the change of mechanical properties, such as hardness and Young's modulus, after nanocutting process.
authors: College of Mechanical Science & Engineering, Jilin University, Renmin Street 5988, Changchun, Jilin 130025, China. hwzhao@jlu.edu.cn.
authors: Lin
authors: L
authors: Zhang
authors: Hu
authors: H
authors: Huang
authors: Hongwei
authors: H
authors: Zhao
authors: Zhichao
authors: Z
authors: Ma
authors: Yihan
authors: Y
authors: Yang
authors: Xiaoli
authors: X
authors: Hu
references: Nature. 2002 Jul 18;418(6895):307-10
references: 12124619
references: Nat Mater. 2009 Feb;8(2):95-100
references: 19151703
references: Phys Rev B Condens Matter. 1986 Jun 15;33(12):7983-7991
references: 9938188