| WANG Gui-lin,YU Ai-bing,YUAN Jian-dong,LI Ke-fan,ZOU Pian,WU Sen-kai.Molecular Dynamics Simulation of Hot Pressing Diffusion Process between Diamond/Ti Interface[J],51(8):435-442 |
| Molecular Dynamics Simulation of Hot Pressing Diffusion Process between Diamond/Ti Interface |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.08.040 |
| KeyWord:hot pressing diffusion molecular dynamics diamond Ti simulation |
| Author | Institution |
| WANG Gui-lin |
School of Mechanical Engineering and Mechanics, Ningbo University, Zhejiang Ningbo , China |
| YU Ai-bing |
School of Mechanical Engineering and Mechanics, Ningbo University, Zhejiang Ningbo , China |
| YUAN Jian-dong |
School of Mechanical Engineering and Mechanics, Ningbo University, Zhejiang Ningbo , China |
| LI Ke-fan |
School of Mechanical Engineering and Mechanics, Ningbo University, Zhejiang Ningbo , China |
| ZOU Pian |
School of Mechanical Engineering and Mechanics, Ningbo University, Zhejiang Ningbo , China |
| WU Sen-kai |
School of Mechanical Engineering and Mechanics, Ningbo University, Zhejiang Ningbo , China |
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| Abstract: |
| The atomic diffusion and TiC formation process between diamond and Ti during hot pressing diffusion process were simulated with molecular dynamics software. The potentials function of modified embedded atom method (MEAM) was used to describe the interactions between Ti, C and Ti—C. The simulation process was divided into three stages:relaxation, hot pressing and thermal insulation. The thicknesses of the atomic diffusion zone between diamond and Ti, as well as the diffusion speed of atoms and the bonding process of TiC were simulated. A hot pressing diffusion experiment of polycrystalline diamond and titanium foil was carried out to verify the results of molecular dynamics simulation. Ti coating was fabricated on surface of polycrystalline diamond with hot pressing diffusion method. A scanning electron microscope was used to observe the interface between polycrystalline diamond and Ti coating, and conducted an EDS analysis of the interface. An X-ray diffractometer was used to analyze the phase compositions of the interface between polycrystalline diamond and Ti. The simulation results show that in the three stages of relaxation, hot pressing and thermal insulation, the thickness of the diffusion zone between diamond and Ti is 0.870 9 nm, 0.888 9 nm and 2.056 5 nm, respectively. From the relaxation to the hot pressing stage, the thickness of the diffusion zone between diamond and Ti increases by 2.07%. From the hot pressing to the thermal insulation stage, the thickness of the diffusion zone between diamond and Ti increases by 131.35%. The slope of the mean square displacement curve of C atoms is 1.877 4×10‒5, and the slope of the mean square displacement curve of Ti atoms is 1.016 7×10‒5. The slope of the mean square displacement of C atoms is 84.66% faster than that the slope of the mean square displacement of Ti atoms. After a relaxation of 20 ps, the free bonds of C atoms near to Ti atoms. In the process of 100 ps hot pressing, a small amount of Ti—C bonds are formed between C atoms and Ti atoms. During the 500 ps thermal insulation process, a large number of Ti—C bonds are formed between the interface of diamond and Ti. The experimental results show that the interface morphology of polycrystalline diamond and titanium coating present a tight and smooth bonding state. The thickness of the diffusion zone between the polycrystalline diamond and Ti interface is 5.7 μm measured by EDS method, and TiC diffraction peaks are detected in the XRD pattern of the interface between polycrystalline diamond and Ti. The research results show that there is obvious atomic diffusion phenomenon between C and Ti atoms, and diffusion zone with a certain thickness is formed during the hot pressing diffusion of diamond and Ti. During the hot pressing diffusion process of interface region between diamond and Ti, the diffusivity and diffusion rate of C atoms is faster than that those of Ti atoms, and a Ti—C bond is formed within the diffusion interface. A chemical combination between diamond and Ti coating is formed. It helps to improved the bonding strength between the diamond surface and the matrix material. |
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