Abstract Self-crack-healing by oxidation of a pre-incorporated healing agent is an essential property high-temperature structural ceramics for components with stringent safety requirements, such as turbine blades in aircraft engines. Here, we report new approach self-healing design containing 3D network activator, based on insight gained clarifying the mechanism. We demonstrate that addition small amount typically doped MnO localised fracture path, selected appropriate thermodynamic...

Self‐crack‐healing behavior under a combustion gas atmosphere with low oxygen partial pressure , is important for actualizing ceramic turbines, but to date only self‐crack‐healing in air has been investigated. In this study, we investigated crack‐healing behaviors at 1273–1773 K several levels of . Crack‐healing atmospheres gave rise the complete strength recovery cracked specimens, resulting from passive oxidation. Based on obtained results, kinetics by was expressed as function healing...

The available temperature range of the self-healing induced by high oxidation SiC can be controlled particle size contained particles. In this study, three types alumina–SiC composites were prepared. sizes 270, ∼30 nm, and less than 10 nm. abilities estimated strength recovery behavior at several temperatures.

Abstract A novel numerical simulation method based on finite element analysis ( FEA ), which can evaluate the fracture probability caused by characteristics of flaw distribution, is considered an effective tool to facilitate and increase use ceramics in components members. In this study, we propose methodology predict scatter ceramic strength. Specifically, data microstructure distribution (i.e., relative density, size aspect ratio pore, grain size) are taken as input values reflected onto...

To improve fracture toughness and encourage excellent self‐crack‐healing ability, mullite/SiC particle/SiC whisker multi‐composites composites were hot pressed. The crack‐healing abilities mechanical properties of these sintered investigated. Based on the obtained results, usefulness mullite composite as a material for springs was discussed. part mullite/15 vol% SiC whisker/SiC 10 particle containing healed cracks retained high reliability over whole measured temperature range. When ability...

The most prominent effect of the weakest link theory, which is used to derive Weibull statistics ceramic strength, size effect. In this study, we analyze on strength using finite element analysis (FEA) methodology previously proposed by authors. FEA methodology, data microstructure distribution (i.e., relative density, size, and aspect ratio pore grain size) are considered as input parameters a continuum damage model via fracture mechanical model. Specifically, examine five sizes rectangular...

Abstract The phenomenon caused by the competition between self‐healing and crack propagation of fiber‐reinforced ceramics was succeeded to be quantified as a new mechanical function. To quantify, it measured in detail that creep deformation time variation composite under various stresses. In particular, detailed analysis will carried out focusing on rate. When tensile stress 100 MPa applied composite, initially large rate decreased with time, eventually reaching zero. This behavior is...

Abstract An optimization method for lowering the effective self‐healing temperature of fiber‐reinforced ceramics (shFRC) was investigated using B 4 C as a improver. selected based on its ability to oxidize at lower temperatures than SiC, typical agent. C/SiC powder mixtures were studied their high‐temperature oxidation behavior, revealing reaction initiation around 600°C during constant heating rate. At 1000°C, accelerated SiC by 15 times. Several shFRCs with C/ interlayer fabricated...

Abstract In this study, a finite element analysis was performed to evaluate the effect of aspect ratios and dielectric constants microdefects, such as pores, secondary phases, grain boundary on electric field enhancement using maximum factor. For defect part with lower constant than solid part, including pores ratio decreases (it becomes longer in direction perpendicular field), factor at lateral surface higher. On other hand, for higher exact opposite behavior observed. Moreover, it also...

ABSTRACT Structural ceramics are brittle and sensitive to flaws. As a result, the structural integrity of ceramic component may be seriously affected by inherent Self‐crack‐healing is an excellent answer this problem. At moment, however, there no technique heal embedded Therefore, guarantee reliability components demanded, thus using crack healing followed proof test was developed K. Ando et al. accomplish this. With technique, testing mechanical behaviour crack‐healed zone very important...

Simple methodology for evaluating availability of self-healing agent has been established from the investigation on relationship between oxidation behavior and phenomena. The consistency was discussed by comparison in lower bound available temperature range ( T H-low ) mullite/TiSi 2 composite. From thermo-gravity differential analysis, 10-h healing ([Formula: see text]) estimated to be 563°C. On other hand, value experimentally determined 600°C strength recovery tests. These values showed a...

The swelling ability of LaNi5 for application to hydrogen-storage-alloy (HSA) actuator is discussed through the measurement ratio in hydrogen. HSA driven by hydrogen pressure change causing HSA. one candidate materials actuators as well palladium. Some prototypes using have been fabricated; however, kinetic itself has not investigated. In this paper, authors investigated static and powder under atmosphere. results showed that increased 0.12 at phase transition pressure. Response time...

Abstract A method to enhance the temperature range in which continuous self-healing fiber-reinforced ceramics (shFRCs) can self-heal is proposed obtain a new high-temperature structural material. The effect of TiSi 2 oxidation on was investigated using SiC, typical agent, and , oxidizes at lower than SiC. Mixtures SiC powders were prepared by wet-mixing, changes their behavior thermogravimetry/differential thermal analysis. 1000 °C enhanced rate 2–3 times. shFRC consisting an Al O 3 matrix,...

A new synthetic method of forming the gamma‐phase aluminum oxynitride (alon) has been proposed. alon successfully synthesized by DC nitrogen plasma arc using alpha‐Al 2 O 3 and AlN as starting materials. Alon rapidly forms in a liquid state under thermal plasma. The obtained lattice parameter determined function concentration Al . Evaporation takes place during melting. condensed from vapor consists nanoscale‐sized spherical particles, these particles are single crystals. evaporation...

The experimental method for the high‐temperature reaction equilibria in AlN‐Al 2 O 3 system has been established. equilibrium N ‐CO gas compositions coexisting with AlN‐ Al ‐graphite have successfully measured by quadrupole mass spectrometry and chromatography. From obtained results, standard Gibbs energy change of forming AlN carbothermal nitridation is determined at temperatures ranging from 1723 to 1899 K: image result, formation third‐law enthalpy 298.15 K are derived as disagreement...