Microstructural investigation of diamond-SiC composites produced by pressureless silicon infiltration

Matthey, Björn; Höhn, Sören; Wolfrum, Anne-Kathrin; Mühle, Uwe; Motylenko, Mykhaylo; Rafaja, David; Michaelis, Alexander; Herrmann, Mathias

doi:10.1016/j.jeurceramsoc.2016.12.008

Cited by 45 publications

(29 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 11.6% layer volume fraction is necessitated by mesh resolution, since a finer mesh would be required to resolve a much thinner layer. The default material for this layer is SiC, based on the real sample, but graphite and diamond layers are also studied to obtain further understanding, since these have been observed in other diamond-SiC materials [ 12 , 14 , 16 ]. Effects of these different compositions on local and global mechanical behaviors are revealed in what follows next.…”

Section: Phase Field Results: Bulk and Layer Composition Effectsmentioning

confidence: 99%

“…Intrinsic stacking fault energy

is associated with a twin boundary energy per unit (one-sided) area [ 26 , 46 , 53 ]. The experimental value [ 60 ] is notably low, leading to profuse stacking faults in addition to deformation twins [ 14 ]. Interpolation constant

is justified in [ 26 , 32 , 33 ].…”

Section: Materials and Microstructuresmentioning

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%

“…The SiC phase is intended to increase toughness and ductility, through a variety of crack mitigation mechanisms that have been sought in diamond-based materials via microstructure alterations [ 22 ]. During material production, the SiC phase can infiltrate GB regions, producing lower overall porosity, graphite content, and fewer debonded diamond-diamond particle contacts than would be present in polycrystalline diamond alone [ 11 , 14 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

et al. 2021

View full text Add to dashboard Cite

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%.

show abstract

Section: Phase Field Results: Bulk and Layer Composition Effectsmentioning

confidence: 99%

“…Intrinsic stacking fault energy

is justified in [ 26 , 32 , 33 ].…”

Section: Materials and Microstructuresmentioning

confidence: 99%