Microstructure and anisotropy of mechanical properties of graphene nanoplate toughened Al2O3-based ceramic composites

Abstract

Graphene nanoplate (GNP)-toughened Al 2 O 3-based ceramic composites were fabricated by the hot-pressing method. The ceramic composites prepared in this way exhibited anisotropy in their mechanical properties. The fracture toughness and flexural strength of the ceramic composites were measured in the vertical to hot-pressing direction (VHPD) and determined to be as high as 6.2 MPa•m 1/2 and 461 MPa, respectively, with GNP contents of 0.75 vol%, which were improvements of 38% and 39%, respectively, over the values measured in the parallel to hot-pressing direction (PHPD). Scanning electron microscope (SEM) observations indicated that GNPs parallel to each other and perpendicular to the hot-pressing direction are the primary explanation for the mechanical property anisotropy. The energy release rate of the crack deflection was calculated, demonstrating the effect of the GNP orientation on the mechanical properties.

Embedding two-dimensional graphene array in ceramic matrix

“…These values far exceed those of other carbon-reinforced ceramics (38,42,(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60). In terms of energy, the critical strain energy release rates for the brittle monolithic ceramics SiO 2 , Al 2 O 3 , and ZrO 2 are 8.9 ± 2, 86.6 ± 3, and 91.7 ± 4 J•m −2 , respectively.…”

Effect of MXene on Oxygen Ion Conductivity of Sm0.2Ce0.8O1.9 as Electrolyte for Low Temperature SOFC

“…1) Ti3C2Tx located at the interface of SDC grains by growing firmly during the high-temperature sintering process that could deflect the growth of micro-cracks. It results in the stress release and the hardness and toughness increasing; 2) Ti3C2Tx anchored at the grain boundary could enhance the interfacial friction between the SDC [19][20][21]. The conductivities of the SDC and 5wt.%Ti3C2Tx/SDC membranes are depicted in fig.…”

“…The fracture toughness of SDC and 5wt.%Ti3C2Tx/SDC membrane composite electrolyte samples was investigated by indentation method (Eq. (1)), which is calculated by the following equation [19,20]. KIC = 0.203*HV*a 2 *c -1.5 , (1) where KIC is fracture toughness, MPa *m 1/2 ; Hv is Vickers hardness, GPa; a is an average length of the indentation diagonal, μm; c is a half of crack length, μm.…”

Effect of graphene orientation on microstructure and mechanical properties of silicon nitride ceramics

“…The binding force of monolayer graphene with each other is very weak, while the Young's modulus of graphene along the graphene sheet is very high. It was found that the Young's modulus of a single crystal graphite along the graphite sheet is 1020 GPa against 36.5 GPa through the graphite sheet [21].…”

“…Also, the properties of the matrix and reinforcement are denoted as subscript number 1 and 2, respectively. The elastic modulus and Poisson's ratio of single crystal graphite (1020 GPa and 0.165 along graphite sheet and 36.5 GPa and 0.012 through graphite sheet) were used as that of graphene [21]. The elastic modulus and Poisson's ratio of Si 3 N 4 are 324 GPa and 0.26, respectively [12].…”