Modeling of effective design of high pressure anvils used for large scale commercial production of gem quality large single crystal diamond

Han, Qing; Li, Mingzhe; Jia, Xiaopeng; Ma, Hongan; Li, Yuefen

doi:10.1016/j.diamond.2011.05.017

Cited by 24 publications

(9 citation statements)

References 12 publications

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“…We can divide the symmetric LV-CHPA into four equal parts and only analyze one part of it as the model, using the static analysis to simulate the stress of the WC anvils under the highest pressure point. [12] A high order 3D 20-node solid element (SOLID186) is applied to the 3D model meshes, and all elements are fully isoperimetric. The contact elements (Targe170 and Contact174) applied to the contact surface are chosen in the model.…”

Section: Fe-model and Simulation Resultsmentioning

confidence: 99%

Hybrid-toroidal anvil: a replacement for the conventional WC anvil used for the large volume cubic high pressure apparatus

Han

Yang

Jia

et al. 2014

High Pressure Research

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We propose a design and operation of a hybrid-toroidal anvil used for the large volume cubic high pressure apparatus (LV-CHPA), such that it is possible to obtain a higher sintered quality, less weight and cost of tungsten carbide (WC) anvil than the conventional anvil. We use the finite element simulations to show the distributions of the stress on the surface and in the bulk of the WC anvils, and conclude that, for a given load on the hybrid-toroidal anvil, the volume of the compressed press medium has increased by 4.88%, and the rate of the transmitted pressure has increased by 6.72% compared with the conventional anvil. Furthermore, the advantages of the hybrid-toroidal anvil are that the movement of anvils increases by 37.14% and the growth rate of the fatigue crack decreases by 40%. This has been proved by the high pressure experiments. This work gives an approach to optimize the WC anvils used for the LV-CHPA and presents a simple method to achieve the higher sample pressure and the larger sample volume.

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Section: Fe-model and Simulation Resultsmentioning

confidence: 99%

Hybrid-toroidal anvil: a replacement for the conventional WC anvil used for the large volume cubic high pressure apparatus

Han

Yang

Jia

et al. 2014

High Pressure Research

Self Cite

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“…Optical microscopy (OM) was employed to observe the morphology of filiform defects in diamond. Finite element modeling details and material parameters were obtained from previous reports and the COMSOL material library. − The boundary conditions across the interface between the growth diamond, seed bed, and catalyst alloy were assumed to be always bonded, resulting in no relative motion between them. A finite element model was used for transient analysis to simulate the thermoelastic stress of a synthetic diamond-seed bed-catalyst alloy.…”

Section: Methodsmentioning

confidence: 99%

Defect and Stress Reduction in High-Pressure and High-Temperature Synthetic Diamonds Using Gradient Cooling Technology

Chen

Zhang

et al. 2020

Crystal Growth & Design

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In order to eliminate filiform defects in high-pressure and high-temperature synthetic diamonds, we have developed a gradient cooling technology and applied it during the synthesis assembly cooling process used during the later stage of diamond synthesis. Finite element simulations showed that the von Mises stress at the end of the synthesis process varied greatly inside the diamond. The rapid thermoelastic stress relief and higher thermoelastic stress generated inside the diamond during rapid cooling of synthesis assembly were the root causes of filiform defects, which were completely eliminated from the diamond interior at a gradient cooling time of 300 min. Raman measurements indicated that the crystalline quality was higher and the compressive stress was lower in the diamond obtained using gradient cooling technology than in the diamond obtained using the traditional rapid cooling technology. This work improves the understanding of the origin of filiform defects in diamond and also provides an effective method for obtaining high-quality diamonds.

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“…To obtain generic results, we considered the simplest model for isotropic, linearly elastic material. Furthermore, the elastic constants are as follows: Young's modulus E = 578 GPa, Poisson ratio ν = 0.21 for tungsten carbide; and E = 210 GPa, ν = 0.29 for alloy steel [20,21]. Herein, the von Mises yield criterion is employed to assess whether the failure occurs for tungsten carbide cylinder and alloy steel supporting rings.…”

Section: Materials Modelmentioning

confidence: 99%

Strength Analysis of a Novel High-Pressure Die with Double-Layered Split Structure

Zhuo

et al. 2018

Metals

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A novel double-layered split die (DLSD) was designed to have higher pressure-bearing capacity and larger sample cavity volume. In DLSD, the cylinder and first layer supporting ring are split into several blocks. It has a prismatic cylinder and a quasi-prismatic sample cavity. The stress distribution of DLSD was investigated and compared with that of the conventional belt-type die (BTD) and a single-layered split die (SLSD) by the finite element method. The results show that the SLSD can only decrease the stress of the cylinder as there remains significant stress on the first layer supporting ring. However, the novel DLSD can, remarkably, decrease the stress placed on the cylinder and first layer supporting ring simultaneously due to the improvement of the stress states. Additionally, the maximum stress and pressure-bearing capacity of DLSD with different numbers of split blocks were further investigated. It is concluded that the maximum stress of the cylinder increases gradually with an increase in the number of split blocks. Meanwhile, the pressure-bearing capacity decreases accordingly. The experiments show that the pressure-bearing capacities of DLSD with 4 and 8 split blocks are all remarkably higher than that of the BTD. DLSD with 4 split blocks has relatively higher pressure-bearing capacity. This work presents a promising high-pressure die with a double-layered split structure for the synthesis of superhard materials.

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Modeling of effective design of high pressure anvils used for large scale commercial production of gem quality large single crystal diamond

Cited by 24 publications

References 12 publications

Hybrid-toroidal anvil: a replacement for the conventional WC anvil used for the large volume cubic high pressure apparatus

Hybrid-toroidal anvil: a replacement for the conventional WC anvil used for the large volume cubic high pressure apparatus

Defect and Stress Reduction in High-Pressure and High-Temperature Synthetic Diamonds Using Gradient Cooling Technology

Strength Analysis of a Novel High-Pressure Die with Double-Layered Split Structure

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