However, during nanocutting process of materials, this assumption is not reasonable since the cutting tool edge radius is on the same scale as the undeformed chip thickness. Thus, the simulation has been done with the cutting edge radius of 2

nm. The spherical indenter contained 36,259 atoms with AZD2014 a radius of 50.0 Å. The motions of the atoms in the Newton and thermostat atoms are assumed to follow Newton’s law of motion which can be computed from the interatomic forces as follows: (1) where a ix represents the i atom’s acceleration in the X direction, m i is the mass of the i atom, F ix is the interaction force between the i atom by the j atom in the X direction, x i indicates the i atom’s X-coordinate, and V is the potential energy. The temperature of atoms during the machining simulation can be calculated using the conversion between the kinetic energy and temperature as ARRY-438162 mw follows: (2) where N is the number of atoms in

groups, v i represents the velocity of the i atom, k b is the Boltzmann constant which is equal to 1.3806503 × 10−23 J/K, and T represents the temperature on atoms. In order to keep the temperature constant during the nanocutting process and nanoindentation process, in other words, ensuring reasonable heat conduction outwards from the Newtonian atom zone [10], the thermostat atom zone is set to absorb the heat from the specimen. When the temperature of the thermostat atom zone is higher than the preset one of 296 K, the velocity rescaling method as shown in Angiogenesis inhibitor Equation 3 [11] is used to control the temperature of the thermostat atom zone and

absorb the heat towards the Newtonian atom zone. The direct velocity scaling method ID-8 was employed to maintain the total kinetic energy at a constant value. The velocity of every atom in the thermostat atom zone needed to be scaled at every integrating step, and the velocity scaling factor is as follows: (3) Selection of potential energy function In this paper, there are two kinds of atoms in the MD simulation model, which are C and Cu atoms. Therefore, there are three different atomic interactions between them, which are the interaction between single-crystal copper atoms (Cu-Cu), the interaction between diamond atoms (C-C), and the interaction between copper atoms and diamond atoms (Cu-C) or (C-Cu). The potential energy function affects the accuracy of the simulation which governs the reliability of results. Between copper atoms in the specimen, the embedded atom method (EAM) potential [12] was applied to describe the Cu-Cu interaction. The EAM potential, which evolved from the density function theory, is based on the recognition that the cohesive energy of a metal is governed not only by the pair-wise potential of the nearest neighbor atoms, but also by embedding energy related to the ‘electron sea’ in which the atoms are embedded.