Interfacial zone surrounding the diamond in reaction bonded diamond/SiC composites: Interphase structure and formation mechanism

Zhang, Yuying; Hsu, Chun‐Yen; Karandikar, Prashant; Ni, Chaoying

doi:10.1016/j.jeurceramsoc.2019.08.019

Cited by 29 publications

(17 citation statements)

References 30 publications

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“…The model of Section 2 , Section 3 and Section 5 is extended to account for processing defects, namely graphitic inclusions and pores. Graphite is assumed to present itself in the form of thin layers or lamellae between fine matrix grains, especially in the vicinity of SiC-diamond and SiC-SiC interfaces [ 14 , 15 , 16 ]. Pores also tend to arise in the vicinity of grain and phase boundaries, rather than within individual crystals.…”

Section: Phase Field Theory: Defective Matrix and Gb Regionsmentioning

confidence: 99%

“…Physical dimensions of these entities are typically on the order of 10 nm, though sizes may vary between several and several hundred nm. These defects are around two orders of magnitude smaller than the bulk diamond grain size

[ 12 , 13 , 14 , 15 ]. Residual silicon (Si) can also appear in small inclusions depending on processing, but is omitted in the present study.…”

Section: Phase Field Theory: Defective Matrix and Gb Regionsmentioning

confidence: 99%

“…Different microstructures of diamond-SiC composites can be achieved depending on choices and proportions of starting materials and processing routes [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 103 ]. Theoretically dense materials can be produced via infiltration of inter-crystalline regions by the matrix phase [ 11 , 16 ].…”

Section: Phase Field Theory: Defective Matrix and Gb Regionsmentioning

confidence: 99%

“…The material consists of diamond and silicon carbide (SiC) crystals with complex spatial and size distributions of grains. Representative microstructures and processing routes for this material system can be found in [ 10 , 11 , 12 , 13 , 14 , 15 ]. In the material studied herein, disparities exist in typical grain sizes among the primary (diamond) and secondary (SiC) phases, with diamond grains tending to be at least an order of magnitude larger, with mean sizes in tens of microns.…”

Section: Introductionmentioning

confidence: 99%

“…In the material studied herein, disparities exist in typical grain sizes among the primary (diamond) and secondary (SiC) phases, with diamond grains tending to be at least an order of magnitude larger, with mean sizes in tens of microns. Furthermore, nanocrystalline SiC encases larger grains, and defects such as pores and graphitic inclusions may be present [ 14 , 15 ]. When graphitic layers at diamond-SiC interfaces are abundant, indentation hardness is compromised [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

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A Multi-Scale Approach for Phase Field Modeling of Ultra-Hard Ceramic Composites

et al. 2021

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Diamond-silicon carbide (SiC) polycrystalline composite blends are studied using a computational approach combining molecular dynamics (MD) simulations for obtaining grain boundary (GB) fracture properties and phase field mechanics for capturing polycrystalline deformation and failure. An authentic microstructure, reconstructed from experimental lattice diffraction data with locally refined discretization in GB regions, is used to probe effects of local heterogeneities on material response in phase field simulations. The nominal microstructure consists of larger diamond and SiC (cubic polytype) grains, a matrix of smaller diamond grains and nanocrystalline SiC, and GB layers encasing the larger grains. These layers may consist of nanocrystalline SiC, diamond, or graphite, where volume fractions of each phase are varied within physically reasonable limits in parametric studies. Distributions of fracture energies from MD tension simulations are used in the phase field energy functional for SiC-SiC and SiC-diamond interfaces, where grain boundary geometries are obtained from statistical analysis of lattice orientation data on the real microstructure. An elastic homogenization method is used to account for distributions of second-phase graphitic inclusions as well as initial voids too small to be resolved individually in the continuum field discretization. In phase field simulations, SiC single crystals may twin, and all phases may fracture. The results of MD calculations show mean strengths of diamond-SiC interfaces are much lower than those of SiC-SiC GBs. In phase field simulations, effects on peak aggregate stress and ductility from different GB fracture energy realizations with the same mean fracture energy and from different random microstructure orientations are modest. Results of phase field simulations show unconfined compressive strength is compromised by diamond-SiC GBs, graphitic layers, graphitic inclusions, and initial porosity. Explored ranges of porosity and graphite fraction are informed by physical observations and constrained by accuracy limits of elastic homogenization. Modest reductions in strength and energy absorption are witnessed for microstructures with 4% porosity or 4% graphite distributed uniformly among intergranular matrix regions. Further reductions are much more severe when porosity is increased to 8% relative to when graphite is increased to 8%.

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Section: Phase Field Theory: Defective Matrix and Gb Regionsmentioning

confidence: 99%

[ 12 , 13 , 14 , 15 ]. Residual silicon (Si) can also appear in small inclusions depending on processing, but is omitted in the present study.…”

Section: Phase Field Theory: Defective Matrix and Gb Regionsmentioning

confidence: 99%