scholarly journals Graphitization Behavior of Single Crystal Diamond for the Application in Nano-Metric Cutting

2018 ◽  
Vol 14 (5) ◽  
pp. 377-383 ◽  
Author(s):  
Qingshun Bai ◽  
Zhiguo Wang ◽  
Yongbo Guo ◽  
Jiaxuan Chen ◽  
Yuanjiang Shang

Background: Graphitization behavior of diamond has received an increasing interest in nanoscale machining of some hard and brittle materials. Diamond has always been an important and excellent tool material in cutting area. However, the graphitization of the diamond tool is inevitable when it was used in special conditions. It is indicated that the graphitization of diamond crystal has great influence on the wear resistance of diamond cutting tool. The graphitization behavior needs to be investigated extensively in nanoscale with an atomic view. Molecular dynamics simulation provides a useful tool for understanding of the graphitization mechanism of diamond. The investigation on graphitization behavior of single crystal diamond can also provide a useful reference for the application of diamond cutting tool. Materials and Methods: In this paper, a molecular dynamics (MD) diamond crystal model is built to examine the graphitization behavior of diamond under various conditions. The sixfold ring method was employed to identify the structural characteristics of graphite and diamond. The effects of temperature and crystal orientation on the graphitization of diamond have been revealed. Considering the effect of temperature, the anisotropy of diamond graphitization against various crystal planes is presented and discussed carefully. The nano-metric cutting model of diamond tool evaluated by the sixfold ring method also proves the graphitization mechanisms in atomic view. Results: Results indicate that the sixfold ring method is a reliable method to evaluate the graphitization behavior of diamond crystal. There exists a critical temperature of the graphitization of diamond. The results also show that {111} plane is more easy to get graphitization as compared with other crystal planes. However, {100} plane of diamond model presents the highest antigraphitization property. Conclusion: The obtained results have provided the in-depth understanding on the wear of diamond tool in nano-metric machining and underpin the development of diamond cutting tool.

1989 ◽  
Vol 55 (2) ◽  
pp. 347-353
Author(s):  
Masanori Yoshikawa ◽  
Kunihiko Kikuchi ◽  
Tadao Tsukada ◽  
Kazuyuki Sasajima

2009 ◽  
Vol 60-61 ◽  
pp. 430-434 ◽  
Author(s):  
Xing Li Zhang ◽  
Zhao Wei Sun ◽  
Guo Qiang Wu

In this article, we select corresponding Tersoff potential energy to build potential energy model and investigate the thermal conductivities of single-crystal carbon thin-film. The equilibrium molecular dynamics (EMD) method is used to calculate the nanometer thin film thermal conductivity of diamond crystal at crystal direction (001), and the non-equilibrium molecular dynamics (NEMD) is used to calculate the nanometer thin film thermal conductivity of diamond crystal at crystal direction (111). The results of calculations demonstrate that the nanometer thin film thermal conductivity of diamond crystal is remarkably lower than the corresponding bulk experimental data and increase with increasing the film thickness, and the nanometer thin film thermal conductivity of diamond crystal relates to film thickness linearly in the simulative range. The nanometer thin film thermal conductivity also demonstrates certain regularity with the change of temperature. This work shows that molecular dynamics, applied under the correct conditions, is a viable tool for calculating the thermal conductivity of nanometer thin films.


2009 ◽  
Vol 407-408 ◽  
pp. 359-362 ◽  
Author(s):  
Takehisa Yoshikawa ◽  
Masayuki Kyoi ◽  
Yukio Maeda ◽  
Tomohisa Ohta ◽  
Masato Taya

Patterning of numerous microlenses on a surface improves the optical performance of components such as liquid crystal displays. A cutting method using a diamond tool is examined to fabricate a molding die that employs arbitrary array patterns to mold millions of microlenses. The present paper investigates machining of microlenses on the order of 2 kHz, using a piezo-actuated micro cutting unit and a synchronous control system of the cutting unit with an NC controller. Experiments using this system revealed that it is possible to machine a large number of microlenses on a molding die with high precision.


2014 ◽  
Vol 625 ◽  
pp. 155-160
Author(s):  
Lai Zou ◽  
Ming Zhou

Ultra-precision diamond cutting of ferrous metals has not been successful in application due to significant tool wear. In this work, numerical simulations and experimental investigations are presented in order to study the interface diffusion between diamond tool and workpiece materials. A diffusion model with respect to carbon atoms from diamond tool penetrating into chips and machined surface was established. The numerical simulation results of the diffusion process reveal that the distribution laws of carbon atoms concentration have a close relationship with diffusion distance, diffusion time and the original carbon concentration of the work material. In addition, diamond face cutting tests of die steels with different carbon content are conducted at different depth of cuts and feed rates to verify the previous simulation results. The wear morphology of rake face and flank face of diamond tool were detected by scanning electron microscopy. Energy dispersive X-ray analysis was proposed to investigate the change in chemical composition of the chips and machined surface. The results of this work benefit for a better understanding on the diffusion wear mechanism in single crystal diamond cutting of ferrous metals.


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