Nacre-like alumina with unique high strain rate capabilities

Evers, Koen; Falco, S.; Grobert, Nicole; Todd, Richard I.

doi:10.1016/j.jeurceramsoc.2019.09.015

Cited by 30 publications

(19 citation statements)

References 36 publications

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“…Finally, hot pressing of anisotropic powder can lead to a simple fabrication of NLA by loading the powder directly into the dye and pressing [61]. Hot pressing or field assisted sintering technique (FAST, also called Spark Plasma Sintering) have been used and both lead to the same material properties, despite a shorter processing time obtained with FAST.…”

Section: Process/structure Relationship In Nlasmentioning

confidence: 99%

“…During this temperature increase, the grain size will change, driven by a reduction of the surface energy [77]. The anisotropic grain evolution has been measured for a NLA sample without any interphase [61]. The values are reported in Fig.…”

Section: Process/structure Relationship In Nlasmentioning

confidence: 99%

“…Evers et al [61] used both a split Hopkinson bar test and impact testing to probe the response of hot pressed NLA at strain rate of 500 6 100 s À1 and impact kinetic energies from 1 to 4.5 kJ. The split Hopkinson bar results, shown in Fig.…”

Section: Structure/performance Relationship In Nlasmentioning

confidence: 99%

“…The structure, fabricated by ice-templating and field assisted sintering technique (FAST) sintering first, used micron-sized Al 2 O 3 platelets as bricks and an amorphous SiO 2 1 CaO glass as mortar, with Al 2 O 3 nanoparticles as nano-asperities and bridges. NLAs have been later fabricated through magnetically assisted slip casting (MASC) [52] and hot pressing [61]. With MASC, the NLAs have been first produced with a SiO 2 1 CaO glass secondary phase [52] and more recently using a transient liquid phase (TLP) sintering resulting in an aluminium borate [62] secondary phase.…”

Section: Introductionmentioning

confidence: 99%

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Strong and tough nacre-like aluminas: Process–structure–performance relationships and position within the nacre-inspired composite landscape

Bouville

2020

J. Mater. Res.

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Section: Process/structure Relationship In Nlasmentioning

confidence: 99%

Section: Process/structure Relationship In Nlasmentioning

confidence: 99%

Section: Structure/performance Relationship In Nlasmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Strong and tough nacre-like aluminas: Process–structure–performance relationships and position within the nacre-inspired composite landscape

Bouville

2020

J. Mater. Res.

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“…The alignment of platelets can be achieved by various processes, such as freeze-casting [8] or magnetic assisted slip casting [9]. Recently, it has also been shown that the simple use of unidirectional pressure during sintering allows the platelets to be aligned perpendicularly to the direction of the load [10] [11]. As interfaces between platelets are more favorable to the crack propagation than alumina grains, cracks are deflected along interfaces.…”

Section: Introductionmentioning

confidence: 99%

Interface failure in nacre-like alumina

Henry

Saad

Doitrand

et al. 2020

Journal of the European Ceramic Society

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Among many bioinspired materials contenders, ceramic-ceramic composites based on alumina platelets have recently emerged as a new class of strong and damage-resistant materials. These materials are brick-and-mortar composites, where bricks are single-crystal alumina platelets, and a glassy interphase acts as the mortar. Although several processing approaches have been reported to date, these materials were optimized so far by trial-and-error approaches. Understanding the fracture properties of nacre-like alumina requires the knowledge of the properties of each of its components. However, only the properties of alumina platelets have been evaluated so far. Here we characterize at a micro scale the fracture property of an aluminosilicate glass interphase between alumina platelets. Micro-cantilever specimens prepared by FIB milling are tested under bending in order to characterize the failure of interfaces exhibiting orientations between 0° and 90° with respect to the beam direction, and thus undergoing different combined shear and tensile stress. Failure appears to be mainly driven by the interface opening stress that seems to predominate over shear stress. The apparent fracture stresses vary from 0.5 GPa to 3.0 GPa depending on the interface angle. It results in a maximum opening stress of 0.72 ± 0.18 GPa reached locally at the interface, whereas the apparent tensile fracture stress of a pack of aligned and perpendicular platelets is approximately 3 GPa. These results should help understand the bulk properties of nacre-like alumina composites and future similar materials and enable a rational design of their components and microstructures.

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Bioinspired Stochastic Design: Tough and Stiff Ceramic Systems

Sarvestani

Egmond

Esmail

et al. 2021

Adv Funct Materials

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Ceramics possess desirable stiffness, compressive strength, and thermal properties compared to alternative material classes. Despite this, the adoption of ceramics into advanced industries has been hindered by their inherent brittleness. Using a state-of-the-art manufacturing platform, the authors incorporate disordered microstructural features inspired by those found in natural, impact-resistant organisms using tessellated ceramic cells. To precisely mimic these natural patterns, a disorder parameter is introduced to modulate the stochasticity of the ceramic architectures. By modifying simple geometrical features such as cut depth and the disorder parameter, the energy absorption is dramatically improved, and the stiffness of the system can be tailored. It is found that the stochastic designs exhibit elevated damage tolerance, denoted by higher dynamic energy absorption (up to 330% for the 3rd impact) and stiffness (up to 200% for the 3rd impact) than both monolithic and perfectly hexagonal architectures. The results show a superior multi-hit resistance owing to optimal cut depth and stochasticity which give access to extrinsic toughening mechanisms that can be influenced through design parameters. This highly-scalable, digital manufacturing platform for creating numerically programmable architectures propels the automated production of intelligent, high-performance, and tailorable ceramic systems for industrial applications in aerospace, protective devices, and medicine.

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Nacre-like alumina with unique high strain rate capabilities

Cited by 30 publications

References 36 publications

Strong and tough nacre-like aluminas: Process–structure–performance relationships and position within the nacre-inspired composite landscape

Strong and tough nacre-like aluminas: Process–structure–performance relationships and position within the nacre-inspired composite landscape

Interface failure in nacre-like alumina

Bioinspired Stochastic Design: Tough and Stiff Ceramic Systems

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