Effect of grain boundary sliding on fracture toughness of ceramic/graphene composites
Introduction
Last years, ceramic/graphene composites attracted much attention due to their excellent mechanical properties and high electrical conductivity (see reviews Porwal et al., 2013a, Centeno et al., 2013, Nieto et al., 2017, Miranzo et al., 2017, Ovid'ko, 2015, Glukharev and Konakov, 2018) and original articles (Fan et al., 2010, Walker et al., 2011, Tapaszto et al., 2011, Wang et al., 2011, Kvetkova et al., 2012, Liu et al., 2012a, Liu et al., 2013, Liu et al., 2017, Liu et al., 2018, Nieto et al., 2013, Porwal et al., 2013b, Fan et al., 2014, Lee et al., 2014, Ramirez et al., 2014, Ramirez et al., 2015, Shin and Hong, 2014, Bódis et al., 2015, Mukherjee et al., 2017, Huang et al., 2018, López-Pernía et al., 2018, Obradović and Kern, 2018, Shin et al., 2018, Yin et al., 2018, Zou et al., 2018). The remarkable mechanical properties of such composites (high fracture toughness and bending strength) are related to the extraordinary properties of graphene (Miranzo et al., 2017). In particular, small volume fractions of platelets of multilayer graphene or reduced graphene oxide (RGO), which tend to be located along the grain boundaries of the ceramic matrix, can significantly increase the fracture toughness of ceramics, see, e.g., reviews (Porwal et al., 2013a, Centeno et al., 2013, Nieto et al., 2017, Miranzo et al., 2017, Ovid'ko, 2015, Glukharev and Konakov, 2018). An increase in the fracture toughness of such ceramic/graphene composites is attributed to crack bridging by graphene inclusions, the pull-out of graphene inclusions from the matrix, crack deflection and branching (Walker et al., 2011, Tapaszto et al., 2011, Wang et al., 2011, Kvetkova et al., 2012, Liu et al., 2012aa; Nieto et al., 2013, Porwal et al., 2013b), as well as to the presence of graphene wrinkles and out-of-plane compression of graphene platelets (Miranzo et al., 2017).
In addition to the experimental studies (He et al., 2014, Fan et al., 2010, Walker et al., 2011, Tapaszto et al., 2011, Wang et al., 2011, Kvetkova et al., 2012, Liu et al., 2012a, Liu et al., 2013, Liu et al., 2017, Liu et al., 2018, Nieto et al., 2013, Porwal et al., 2013b, Fan et al., 2014, Lee et al., 2014, Ramirez et al., 2014, Ramirez et al., 2015, Shin and Hong, 2014, Bódis et al., 2015, Mukherjee et al., 2017, Huang et al., 2018, López-Pernía et al., 2018, Obradović and Kern, 2018, Shin et al., 2018, Yin et al., 2018, Zou et al., 2018), the effects of graphene platelet pullout (Zhang et al., 2014, Ramirez and Osendi, 2014, Bobylev and Sheinerman, 2018) and crack deflection (Ovid'ko and Sheinerman, 2015) on fracture toughness of ceramic/graphene or polymer/graphene composites have also been addressed in several theoretical studies. These studies (Zhang et al., 2014, Ramirez and Osendi, 2014, Bobylev and Sheinerman, 2018, Ovid'ko and Sheinerman, 2015) demonstrated that both graphene platelet pullout and crack deflection can increase fracture toughness of ceramics by several tens percent, even for a small volume fraction of graphene. They also showed that for a specified volume fraction of graphene, longer graphene platelets should induce higher toughening associated with more difficult graphene platelet pullout (Bobylev and Sheinerman, 2018).
At the same time, in contrast to the latter result, recently, Porwal et al. (2016) observed a decrease in the fracture toughness of alumina/graphene composites with increasing the lateral graphene platelet dimensions. This effect was attributed to the onset of grain boundary (GB) sliding in the composites where the length of graphene platelets was close to the GB length. However, no explanation was given for the connection between the activation of GB sliding and the observed drop in the fracture toughness of the composites. To fill this gap, in the present study we suggest a model describing crack propagation assisted by GB sliding in ceramic/graphene composites.
Section snippets
Grain boundary sliding assisted crack growth in deformed ceramic/graphene composites. Model
Consider a ceramic/graphene composite in the form of a polycrystalline ceramic matrix and platelets that consist of several atomic layers of graphene or RGO (Fig. 1a). We assume that graphene platelets can be located both in GBs and in grain interiors. Let the examined specimen be under uniaxial uniform tension.
Following the observations (Porwal et al., 2016), suppose that cracks in the composite tend to propagate over GBs. Consider the situation where a flat mode I crack, whose length is much
Critical stress intensity factor for grain boundary sliding assisted crack growth in a ceramic/graphene composite
Now estimate the critical stress intensity factor for GB-sliding-assisted crack growth in a ceramic/graphene composite. To do so, examine a fragment of the composite containing a crack terminated at junction A (Fig. 2). For simplicity, we focus on the simplified case where GB AB contains only one graphene platelet whose cross section in the plane of GB AB represents a rectangle with the length p1 and width p2 (not shown in Fig. 2). For definiteness, assume that the center of the platelet
Results and discussion
To test the model, we put , where d is the grain size, and calculate KIC for three α-alumina/graphene composites examined in Porwal et al. (2016) with the following values of geometric parameters: , nm, nm for the first specimen; , nm, nm for the second specimen; and , nm, nm for the third specimen. Since for the first specimen, p1 is slightly larger than dGB, while our model considers the situation where p1 ≤ dGB, we put
Conclusions
Thus, we have suggested a model describing GB-sliding-assisted crack growth in ceramic/graphene composites. Within the model, high stress concentrations near the tips of GB cracks stopped at triple junctions of GBs induce local GB sliding, which, in turn, results in the formation of new cracks in adjacent GBs. The main pre-existent cracks merge with the new ones, thus providing crack propagation. For the case where the formation and growth of new cracks near the tips of the main cracks assisted
Acknowledgement
The authors acknowledge the support of the Russian Science Foundation (grant 18-19-00255).
References (53)
- et al.
Effects of intergrain sliding on crack growth in nanocrystalline materials
Int. J. Plasticity
(2010) - et al.
Graphene for tough and electroconductive alumina ceramics
J. Eur. Ceram. Soc.
(2013) - et al.
The effect of homogeneously dispersed few-layer graphene on microstructure and mechanical properties of Al2O3 nanocomposites
J. Eur. Ceram. Soc.
(2014) - et al.
Preparation and electrical properties of graphene nanosheet/Al2O3 composites
Carbon
(2010) - et al.
Size effects on intergranular crack growth mechanisms in ultrathin nanocrystalline gold free-standing films
Acta Mater.
(2018) - et al.
Enhancing toughness and strength of SiC ceramics with reduced graphene oxide by HP sintering
J. Eur. Ceram. Soc.
(2018) - et al.
Fracture toughness and toughening mechanisms in graphene platelet reinforced Si3N4 composites
Scr. Mater.
(2012) - et al.
Simultaneous strengthening and toughening of reduced graphene oxide/alumina composites fabricated by molecular-level mixing process
Carbon
(2014) - et al.
Cleavage, dislocation emission, and shielding for cracks under general loading
Acta Metall.
(1986) - et al.
Spark plasma sintering of graphene platelet reinforced zirconia composites with improved mechanical performance
Mater. Sci. Eng. A
(2017)
Mechanical properties of graphene platelet-reinforced alumina ceramic composites
Ceram. Int.
Toughening of zirconia/alumina composites by the addition of graphene platelets
J. Eur. Ceram. Soc.
Grain growth kinetics in microwave sintered graphene platelets reinforced ZrO2/Al2O3 composites
Ceram. Int.
Optimizing the homogenization technique for graphene nanoplatelet/yttria tetragonal zirconia composites: Influence on the microstructure and the electrical conductivity
J. Alloys Compd.
From bulk to cellular structures: a review on ceramic/graphene filler composites
J. Eur. Ceram. Soc.
Plasma sprayed carbon nanotube and graphene nanoplatelets reinforced alumina hybrid composite coating with outstanding toughness
J. Alloys Compd.
Graphene nanoplatelets reinforced tantalum carbide consolidated by spark plasma sintering
Mater. Sci. Eng. A
Properties of 3Y-TZP zirconia ceramics with graphene addition obtained by spark plasma sintering
Ceram. Int.
Grain size effect on crack blunting in nanocrystalline materials
Scripta Mater.
Generation and growth of nanocracks near blunt cracks in nanocrystalline solids
Eur. J. Mech. A
Effect of lateral size of graphene nano-sheets on the mechanical properties and machinability of alumina nano-composites
Ceram. Int.
Graphene reinforced alumina nano-composites
Carbon
Extraordinary toughening enhancement and flexural strength in Si3N4 composites using graphene sheets
J. Eur. Ceram. Soc.
Toughening in ceramics containing graphene fillers
Ceram. Int.
Graphene nanoribbon ceramic composites
Carbon
Comparative study on carbon nanotube- and reduced graphene oxide-reinforced alumina ceramic composites
Ceram. Int.
Cited by (19)
Defect-induced fracture topologies in Al<inf>2</inf>O<inf>3</inf> ceramic-graphene nanocomposites
2024, Materials and DesignCharacterizing the time-dependent external force on the cars’ hood door in accident using deep neural networks
2024, Materials Today CommunicationsStrengthening mechanism of cemented carbide containing Re
2022, Materials Science and Engineering: AGraphene-reinforced ceramics obtained by slip casting and pressureless sintering: Interactions and stability of particles in aqueous environment
2022, Open CeramicsCitation Excerpt :The obtained improvement in fracture toughness is higher than what was reported for similar composites prepared via powder metallurgy route, where fracture toughness was improved by around 1.3–1.5 with similar content of graphene reinforcement [52–54]. Such effect can be attributed to mechanisms previously postulated for such materials, like grain boundary sliding or crack bridging [52,55]. SEM images of selected samples are shown in Fig. 9.
Optimisation of rGO-enriched nanoceramics by combinatorial analysis
2021, Materials and DesignCitation Excerpt :A small fraction of inclusions (0–3 wt%) can be beneficial for the mechanical performance as it leads to material strengthening [5,25,26]. The strengthening arises from rGO filling pores of nanoceramics and interacting with growing cracks [5]. However, a small fraction of inclusions may not provide a desired increase of the electrical conductivity of the composite.