Critical crack-healing condition for SiC whisker reinforced alumina under stress

Nakao, Wataru; Ono, Masato; Lee, Sang Kee; Takahashi, Koji; Ando, Kotoji

doi:10.1016/j.jeurceramsoc.2004.09.021

Cited by 76 publications

(59 citation statements)

References 31 publications

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“…Early work focused on crack healing of surface cracks of polycrystalline UO 2 [21,22], Al 2 O 3 [23] and MgO [24]. Since then, a large number of ceramic materials were demonstrated to exhibit crack healing capability including silicon carbide [25,26], silicon nitride [27,28], single crystalline sapphire [29], alumina [15,30,31], mullite [32,33], zirconia [34], or MAS glass ceramics [35]. The temperatures to initiate healing reaction, however, were found to exceed 0.7-0.9 of the melting temperature of single crystals or equal the sintering temperature of polycrystalline ceramics.…”

Section: Introductionmentioning

confidence: 99%

Generic principles of crack-healing ceramics

Greil

2012

J Adv Ceram

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Abstract:Ceramic materials able to heal manufacture or damage induced microstructure defects might trigger a change in paradigm for design and application of load bearing ceramics. This work reviews thermodynamic and kinetic aspects governing the regeneration of solid contact able to transfer stress between disrupted crack surfaces in ceramics. Major crack healing processes include perturbation of crack-like pores followed by sintering of isolated pores, as well as reaction with an environmental atmosphere and filling of the crack space with an oxidation product. Since thermally activated solid state reactions require elevated temperatures which may exceed 1000 ℃, processes able to trigger crack healing at lower temperatures are of particular interest for transferring into engineering applications. Generic principles of microstructure modifications able to facilitate crack repair at lower temperatures will be considered: (i) acceleration of material transport by grain boundary decoration and grain size reduction, and (ii) reduction of thermal activation barrier by repair filler activation. Examples demonstrating crack healing capability include oxidation reaction of low energy bonded intercalation metal from nano-laminate MAX phases and catalyzed surface nitridation of polymer derived ceramics containing repair fillers.

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Section: Introductionmentioning

confidence: 99%

Generic principles of crack-healing ceramics

Greil

2012

J Adv Ceram

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“…If the crack can be healed under service conditions and the components recover their strength completely, the reliability and lifetime of ceramics components can be increased. Crackhealing behavior under constant or cyclic stress has been systematically studied for Si 3 N 4 /SiC [5,20], mullite/SiC [21,22], Al 2 O 3 /SiC [23], and SiC [17]. Standard precracks were healed, and the samples completely recovered their strength at the healing temperature, even under constant or cyclic stress.…”

Section: Crack-healing Behavior During Servicementioning

confidence: 99%

New Technology for Increasing Through-Life Reliability of Ceramics Components Using Self-Crack-Healing Ability

Ando

Takahashi

Nakao

et al. 2013

Journal of Powder Technology

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Structural ceramics are superior to metallic materials in terms of their high-temperature strengths and critical heat proof temperatures. However, compared to metallic materials, ceramics exhibit lower fracture toughness, so they are more sensitive to flaws such as pores and cracks. The shortness considerably decreases the component reliability. To overcome the shortness, in this study, special attention is paid to structural ceramics with self-crack-healing ability. There are several advantages for using a material with self-crack-healing ability. (1) After an efficient machine operation, the materials are able to self-heal the cracks introduced by the machining. (2) The materials are able to self-heal the cracks introduced during service and recover the strength completely at healing temperature. However, ways of organizing the available knowledge to increase the through-life reliability of ceramics components have not been extensively studied. The authors propose a new concept and the corresponding flowchart. This new concept is a promising technique for increasing the through-life reliability of ceramics components with excellent self-crack-healing ability.

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“…It was shown that ceramics with participation of SiCw in Al 2 O 3 matrix enhanced the mechanical properties significantly, which enabled the cutting of Inconel 718 super-alloy. The Al 2 O 3 ceramics reinforced by SiCw was developed with the objective to improve its fracture toughness and crack healing ability [5]. The used SiC whiskers have diameters between 0.8 and 1.0 μm and lengths from 30 to 100 μm.…”

Section: Introductionmentioning

confidence: 99%