Strength and plastic deformation of polycrystalline diamond composites

Wang, Yanbin; Shi, Feng; Ohfuji, Hiroaki; Gasc, Julien; Nishiyama, Norimasa; Yu, Tony; Officer, T.; Shinmei, Toru; Irifune, Tetsuo

doi:10.1080/08957959.2019.1695254

Cited by 5 publications

(11 citation statements)

References 42 publications

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“…Figure compares the strength of NPD with those of diamond single crystals and PCDCs reported in an earlier study over a wide temperature range . The 2073 K point is from three-point bending tests on single crystals at 1 atm in inert atmosphere .…”

Section: Resultsmentioning

confidence: 91%

“…Stage 1 is elastic, stage 2 shows a rapid increase in strength with strain after yield, and stage 3 exbibits a marked decrease in strain sensitivity as compared to stage 2. For comparison, Sumitomo PCDC data (green) are also plotted. These samples have large grain size of at least several micrometers.…”

Section: Resultsmentioning

confidence: 99%

“…Also plotted in Figure is strength of Sumitomo PCDC (average grain size of 1–2 μm with 1–2% Co in volume, used as a binder) at 1473 K . At 4% strain, the strength of NPD is ∼3 times that of this PCDC, which has the highest strength among all PCDCs reported .…”

Section: Resultsmentioning

confidence: 99%

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Plastic Deformation and Strengthening Mechanisms of Nanopolycrystalline Diamond

et al. 2021

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Bulk nanopolycrystalline diamond (NPD) samples were deformed plastically within the diamond stability field up to 14 GPa and above 1473 K. Macroscopic differential stress Δσ was determined on the basis of the distortion of the 111 Debye ring using synchrotron X-ray diffraction. Up to ∼5(2)% strain, Debye ring distortion can be satisfactorily described by lattice strain theories as an ellipse. Beyond ∼5(2)% strain, lattice spacing d 111 along the Δσ direction becomes saturated and remains constant with further deformation. Transmission electron microscopy on as-synthesized NPD shows well-bonded grain boundaries with no free dislocations within the grains. Deformed samples also contain very few free dislocations, while density of {111} twins increases with plastic strain. Individual grains display complex contrast, exhibiting increasing misorientation with deformation according electron diffraction. Thus, NPD does not deform by dislocation slip, which is the dominated mechanism in conventional polycrystalline diamond composites (PCDCs, grain size >1 μm). The nonelliptical Debye ring distortion is modeled by nucleating dislocations or their dissociated partials gliding in the {111} planes to produce deformation twinning. With increasing strain up to ∼5(2)%, strength increases rapidly to ∼20(1) GPa, where d 111 reaches saturation. Strength beyond the saturation shows a weak dependence on strain, reaching ∼22(1) GPa at >10% strain. Overall, the strength is ∼2–3 times that of conventional PCDCs. Combined with molecular dynamics simulations and lattice rotation theory, we conclude that the rapid rise of strength with strain is due to defect-source strengthening, whereas further deformation is dominated by nanotwinning and lattice rotation.

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

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Plastic Deformation and Strengthening Mechanisms of Nanopolycrystalline Diamond

et al. 2021

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“…Plastic behavior of NPDs compared to conventional PDCs was studied at HP–HT using D-DIA press coupled with X-ray radiography and diffraction [ 190 , 191 , 192 ]. Deformation of PDCs was highly dependent on the binder content and resulted in strong work hardening.…”

Section: Diamonds Properties and Usesmentioning

confidence: 99%

A Review of Binderless Polycrystalline Diamonds: Focus on the High-Pressure–High-Temperature Sintering Process

2022

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Nowadays, synthetic diamonds are easy to fabricate industrially, and a wide range of methods were developed during the last century. Among them, the high-pressure–high-temperature (HP–HT) process is the most used to prepare diamond compacts for cutting or drilling applications. However, these diamond compacts contain binder, limiting their mechanical and optical properties and their substantial uses. Binderless diamond compacts were synthesized more recently, and important developments were made to optimize the P–T conditions of sintering. Resulting sintered compacts had mechanical and optical properties at least equivalent to that of natural single crystal and higher than that of binder-containing sintered compacts, offering a huge potential market. However, pressure–temperature (P–T) conditions to sinter such bodies remain too high for an industrial transfer, making this the next challenge to be accomplished. This review gives an overview of natural diamond formation and the main experimental techniques that are used to synthesize and/or sinter diamond powders and compact objects. The focus of this review is the HP–HT process, especially for the synthesis and sintering of binderless diamonds. P–T conditions of the formation and exceptional properties of such objects are discussed and compared with classic binder-diamonds objects and with natural single-crystal diamonds. Finally, the question of an industrial transfer is asked and outlooks related to this are proposed.

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“…Here the CRSS is defined as the threshold stress of dislocation motion, and the barrier strength is defined as the threshold stress of dislocation reaction with the TB when the activation energy reaches zero 19 . Therefore, at room temperature, the hardness of the diamond is primarily controlled by the behavior of shuffle-set 0°perfect dislocations 16,20 . Therefore, in the present study, the hardness of the int-diamond will be analyzed based on the behavior of shuffle-set 0°perfect dislocations.…”

Section: Dislocation Slip Modes In Int-diamond Grainsmentioning

confidence: 99%

Intersectional nanotwinned diamond-the hardest polycrystalline diamond by design

Xiao

Wen

et al. 2020

npj Comput Mater

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The hardness of nanotwinned diamond (nt-diamond) is reported to be more than twice that of the natural diamond, thanks to the fine spaces between twin boundaries (TBs), which block dislocation propagation during deformation. In this work, we explore the effects of additional TBs in nt-diamond using molecular dynamics (MD) calculations and introduce a novel intersectional nanotwinned diamond (int-diamond) template for future laboratory synthesis. The hardness of this int-diamond is predicted by first analyzing individual dislocation slip modes in twinned grains and then calculating the bulk properties based on the Sachs model. Here we show that the hardness of the int-diamond is much higher than that of nt-diamond. The hardening mechanism of intdiamond is attributed to the increased critical resolved shear stress due to the presence of intersectional TBs in nt-diamond; this result is further verified by MD simulations. This work provides a new strategy for designing new super-hard materials in experiments.

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Strength and plastic deformation of polycrystalline diamond composites

Cited by 5 publications

References 42 publications

Plastic Deformation and Strengthening Mechanisms of Nanopolycrystalline Diamond

Plastic Deformation and Strengthening Mechanisms of Nanopolycrystalline Diamond

A Review of Binderless Polycrystalline Diamonds: Focus on the High-Pressure–High-Temperature Sintering Process

Intersectional nanotwinned diamond-the hardest polycrystalline diamond by design

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