Research On Temperature Field In The Nanometric Cutting Process Of Amorphous Copper By Molecular Dynamics Simulation

Compared with traditional crystal metals, amorphous metals have no microstructure defects such as dislocation, stacking fault and so on. Duo to excellent mechanical properties, soft magnetic properties and chemical properties, amorphous metals have broad application prospects in aerospace field, power transmission field, etc. The microstructure of amorphous is in metastable state and sensitive to temperature. Amorphous metals easily occur brittle fracture and crystalline transition under the influence of external conditions. Amorphous would undergo complex thermos-mechanical deformation in the cutting process. Cutting tool shows obvious adhesive wear phenomenon. The chip has characteristics of high frequency cyclic shear zones. An increasing number of researches suggest that the phenomenons above have a close relation with the characteristics of sensitivity of temperature. Therefore, in view of characteristics of groups of atoms cluster with medium-range and short-range order, the temperature field in the process of nanocutting amorphous copper is researched in the paper by using molecular dynamics in order to lay the theoretical foundation for deep understanding of amorphous metal.Amorphous copper workpiece is obtained by the method of rapid cooling and the change of atomic volume is studied in the process of rapid cooling. The inflection point of the atomic volume rate is obtained through linear fitting to determine glass transition temperature( g=774K) of amorphous copper. Shear strain of amorphous copper is analysed in the process of machining to research shear angle and shear band of amorphous copper. The shortage of the method calculating temperature in molecular dynamics is analysed. A new method of calculating temperature is presented to improve calculating efficiency.The atomic temperature is calculated through the improved calculation method after reasonable grouping in the amorphous copper workpiece. The effects of cutting speed and cutting depth on cutting temperature of tool rake face, chip temperature and machined surface temperature are researched. The influences of cutting speed on temperature are apparent and that of cutting depth is not. The temperature and radial distribution function of machined surfaces are analysed, it is found that the machined surfaces also occur crystallization when the temperature is lower than the glass transition temperature of amorphous copper, which indicates that crystallization is the results of all external conditions.A large number of temperature points are collected to draw temperature contour maps of workpiece layer. Research shows that the temperature gradient of green surface is maximum and temperature gradient of machined surface is minimum. Temperature peak is located below the flank surface of the cutting tool, the peaks of temperature are located in different depths under conditions of cutting parameters. Finally, the distribution of temperature is similar to that of the conventional cutting in small cutting area of nanometric cutting except the location of temperature peaks...