Stress and dislocations in diamond–SiC composites sintered at high pressure, high temperature conditions

Nauyoks, S.; Wieligor, Monika; Żerda, T. W.; Balogh, Levente; Ungár, Tamás; Stephens, Peter W.

doi:10.1016/j.compositesa.2009.02.006

Cited by 19 publications

(7 citation statements)

References 23 publications

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“…This crack deflection will consume a lot of energy and eventually increase the toughness 8,64 . In addition, since dislocations are formed around the reinforcing particles, if the crack encounters these dislocations in its growth path, it inevitably shows a path deviation 65,66 . Overall, these factors have improved the fracture toughness by increasing the reinforcing particles to 5 wt.% of nano β-SiC and 1 wt.% of graphene (Fig.…”

Section: Toughnessmentioning

confidence: 99%

αSiC - βSiC - graphene composites

Razmjoo

Baharvandi

Ehsani

2023

Sci Rep

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In this study, the mechanical properties of the pressureless sintered samples of α-SiC based composite containing 0–3 wt.% graphene and 0–15 wt.% nano β-SiC were investigated. Simultaneous usage of nano β-SiC and graphene and transformation of β-SiC (3C) to α-SiC (6H/4H) resulted in elongation of secondary α-SiC grains, which significantly improved the mechanical properties (e.g. fracture toughness) of SiC ceramics. According to the results, the highest Relative density of 99.04%, Young’s modulus of 537.76 GPa and fracture toughness of 5.73 MPa × m1/2 were obtained in the sample containing 5 wt.% nano β-SiC and 1 wt.% graphene (5B1G). In addition, two methods of measuring bending strength including three-point bending tests and biaxial tests (piston-on-three-ball) were compared. Strip-shaped specimens were prepared for three-point bending test and disc-shaped specimens were prepared for biaxial bending test. Each bending test was evaluated using a universal testing machine. The results showed that the biaxial bending strength is less than the three-point bending strength. Also, the maximum three-point bending strength of 582.01 MPa and biaxial bending of 441.56 MPa were obtained in 5 wt.% Nano β-SiC and 1 wt.% Graphene samples (5B1G). Studies have shown that in addition to the many advantages of using the biaxial bending method, the results have a very similar trend to the three-point bending strength. Also, the most-increased hardnesses of 28.03 GPa and 29.97 GPa were seen in the sample containing 5 wt.% nano β-SiC (5B) with forces of 10 N and 1 N, respectively. One of the effective mechanisms in improving the fracture toughness of α-SiC ceramics is crack deflection/bridging. Also, the difference in thermal expansion of the α-SiC matrix and the reinforcements, leading to the creation of residual stresses between the matrix grains and the reinforcement, is effective in improving the mechanical properties (e.g. strength and fracture toughness).

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Section: Toughnessmentioning

confidence: 99%

αSiC - βSiC - graphene composites

Razmjoo

Baharvandi

Ehsani

2023

Sci Rep

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“…After the milling process, a refined microstructure is obtained with a small crystallite size and high microstrain values; this nanostructured state is induced by the severe deformation accumulated during the milling of the Al matrix [24]. At this stage of the process, the C phase acts as a control agent process preventing the excessive cold welding of the Al particles during the milling process [19]. After the sintering process, the crystallite size grows, and the C phase transforms into the Al 4 C 3 nanophase.…”

Section: Microstructural Analysismentioning

confidence: 99%

Effect on Microstructure and Hardness of Reinforcement in Al–Cu with Al4C3 Nanocomposites

Orozco

Beltrán

et al. 2021

Metals

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By superposition, the individual strengthening mechanisms via hardness analyses and the particle dispersion contribution to strengthening were estimated for Al–C and Al–C–Cu composites and pure Al. An evident contribution to hardening due to the density of dislocations was observed for all samples; the presence of relatively high-density values was the result of the difference in the coefficients of thermal expansion (CTE) between the matrix and the reinforced particles when the composites were subjected to the sintering process. However, for the Al–C–Cu composites, the dispersion of the particles had an important effect on the strengthening. For the Al–C–Cu composites, the maximum increase in microhardness was ~210% compared to the pure Al sample processed under the same conditions. The crystallite size and dislocation density contribution to strengthening were calculated using the Langford–Cohen and Taylor equations from the microstructural analysis, respectively. The estimated microhardness values had a good correlation with the experimental. According to the results, the Cu content is responsible for integrating and dispersing the Al4C3 phase. The proposed mathematical equation includes the combined effect of the content of C and Cu (in weight percent). The composites were fabricated following a powder metallurgical route complemented with the mechanical alloying (MA) process. Microstructural analyses were carried out through X-ray analyses coupled with a convolutional multiple whole profile (CMWP) fitting program to determine the crystallite size and dislocation density.

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“…The existing methods for preparing Dia/SiC composites include high-temperature and high-pressure (HTHP) sintering [ 9 , 10 ], precursor conversion [ 11 ], vacuum discharge plasma sintering [ 12 ], and hot isostatic pressing [ 8 , 13 ]. The application of hot isostatic pressing and HTHP sintering methods to prepare composite materials is limited by their expensive equipment [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Fabrication of Diamond/SiC Composites Using α-Si3N4/Si Infiltration

Xing,

Zhang,

Zhao

et al. 2023

Materials

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Diamond/SiC (Dia/SiC) composites possess excellent properties, such as high thermal conductivity and low thermal expansion coefficient. In addition, they are suitable as electronic packaging materials. This study mainly optimized the diamond particle size packing and liquid-phase silicon infiltration processes and investigated a method to prevent the adhesion of the product to molten silicon. Based on the Dinger–Funk particle stacking theory, a multiscale diamond ratio optimization model was established, and the volume ratio of diamond particles with sizes of D20, D50, and D90 was optimized as 1:3:6. The method of pressureless silicon infiltration and the formulas of the composites were investigated. The influences of bedding powder on phase composition and microstructure were studied using X-ray diffraction and scanning electron microscopy, and the optimal parameters were obtained. The porosity of the preform was controlled by regulating the feeding amount through constant volume molding. Dia/SiC-8 exhibited the highest density of 2.73 g/cm3 and the lowest porosity of 0.6%. To avoid adhesion between the sample and buried powder with the bedding silicon powder, a mixed powder of α-Si3N4 and silicon was used as the buried powder and the related mechanisms of action were discussed.

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Stress and dislocations in diamond–SiC composites sintered at high pressure, high temperature conditions

Cited by 19 publications

References 23 publications

αSiC - βSiC - graphene composites

αSiC - βSiC - graphene composites

Effect on Microstructure and Hardness of Reinforcement in Al–Cu with Al4C3 Nanocomposites

Investigation of the Fabrication of Diamond/SiC Composites Using α-Si3N4/Si Infiltration

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