Strengthening and Toughening Mechanisms of Ceramic Nanocomposites

Ohji, Tatsuki; Jeong, Young-Keun; Choa, Yong‐Ho; Niihara, Koichi

doi:10.1111/j.1151-2916.1998.tb02503.x

Cited by 267 publications

(136 citation statements)

References 43 publications

(58 reference statements)

Supporting

Mentioning

115

Contrasting

Order By: Relevance

“…Even though several models for the mechanisms of nanocomposites have been proposed [10,11], such as a steep R-curve behavior model [12], residual stress model [13], and reduction in the processing defect size model [14], several researchers remain skeptical about nanocomposites [15,16]. These skepticisms result from the fact that the previously proposed strengthening and toughening mechanisms mentioned above do not provide sufficient explanations for all of the characteristics of nanocomposites that have been observed.…”

Section: Introductionmentioning

confidence: 84%

“…Ohji et al [12] proposed a particle-bridge mechanism, whereby crackface shielding results when nano-size particles bridge the crack surfaces. Crack deflection and crack bowing are related to the interactions of a crack front with second-phase inclusions which depend on the differences in the thermoelastic properties of the matrix and inclusions.…”

Section: Previous Modelsmentioning

confidence: 99%

See 1 more Smart Citation

Nanocomposites—a new material design concept

Choi

Araki

2005

Science and Technology of Advanced Materials

183

View full text Add to dashboard Cite

Ceramic-based nanocomposites were reviewed, emphasizing the newly developed concept of material design for ceramics. First, characteristics of the nanocomposites observed by previous researchers were summarized as, significant or moderate improvement in strength, drastic change of the fracture mode from intergranular fracture of monolithic ceramics to transgranular fracture of nanocomposites, moderate enhancement of fracture toughness, improvement of other mechanical properties, and observations of dislocations. Second, several mechanisms proposed previously to explain these characteristics were reviewed. Third, our strengthening and toughening mechanisms of nanocomposites on the basis of dislocation activities were explained. In nanocomposites, the highly localized residual stresses in the matrix grains are generated by the mismatch of thermal expansion coefficients between the matrix and the dispersed particles, and the dislocations are yielded during the cooling process after sintering. These dislocations then release the tensile residual stresses intrinsically existing in the matrix grains of sintered ceramics and improve the strength of the materials. In addition, as these dislocations cannot move at room temperature the sessile dislocations in the matrix operate as nano-crack nuclei in a frontal process zone (FPZ) ahead of the crack tip when the tip of a propagating crack approaches this area. Therefore, the size of the FPZ is expanded and as a result the fracture toughness is improved. Finally, estimation of the critical FPZ size was explained in order to clarify its toughening mechanism in nanocomposites. q

show abstract

Section: Introductionmentioning

confidence: 84%

Section: Previous Modelsmentioning

confidence: 99%

Nanocomposites—a new material design concept

Choi

Araki

2005

Science and Technology of Advanced Materials

183

View full text Add to dashboard Cite

show abstract

“…For a high strength or high modulus reinforcement, this can be beneficial as well. This situation can lead to crack tip bridging, a method of crack blunting [93][94][95].…”

Section: Reinforcementmentioning

confidence: 99%

Improving Hardness and Toughness of Boride Composites Based on AIMgB<sub>14</sub>

Peters

2007

View full text Add to dashboard Cite

“…Examples hereof are aluminium metal composites [15], ceramics [16] or epoxy polymer composites [17]. A composite between aerogel and polymer can be used to combine the properties of the flexible polymers and the highly porous but brittle aerogels.…”

Section: Introductionmentioning

confidence: 99%

Solution electrospinning of particle-polymer composite fibres

Christiansen

Fojan

2016

Manufacturing Rev.

View full text Add to dashboard Cite

-Electrospinning is a fast, simple way to produce nano/microfibers, resulting in porous mats with a high surface to volume ratio. Another material with high surface to volume ratio is aerogel. A drawback of aerogels is its inherent mechanical weakness. To counteract this, aerogels can be embedded into scaffolds. The formation of a particle/polymer composite results in improved mechanical stability, without compromising the porosity. In the presented study, aerogel and poly(ethylene oxide) are mixed into a solution, and spun to thin fibres. Thereby a porous membrane, on the micro-and nano-scale, is produced. The maximum polymer-silica weight-ratio yielding stable fibres has also been determined. The morphology of the fibres at different weight ratios has been investigated by optical microscopy and scanning electron microscope (SEM). Low aerogel concentrations yield few particles located in polymer fibres, whereas higher amounts resulted in fibres dominated by the aerogel particle diameters. The diameters of these fibres were in the range between 13 um to 41 um. The flowrate dependence of the fibre diameter was evaluated for polymer solutions with high particle contents. The self-supporting abilities of these fibres are discussed. It is concluded that selfsupporting polymer/aerogel composites can be made by electrospinning.

show abstract

Strengthening and Toughening Mechanisms of Ceramic Nanocomposites

Cited by 267 publications

References 43 publications

Nanocomposites—a new material design concept

Nanocomposites—a new material design concept

Improving Hardness and Toughness of Boride Composites Based on AIMgB<sub>14</sub>

Solution electrospinning of particle-polymer composite fibres

Contact Info

Product

Resources

About