Al-Al2O3 Composites Research Articles

Microstructural Evaluation of Al-Al2O3 Composites Processed by Stir Casting Technique

The exceptional qualities of aluminum alloys, including their superior thermal properties, high specific strength and low density make them widely employed as industrial materials. By adding a tougher ceramic reinforcement phase to the aluminum matrix phase, aluminum alloy components can perform even better with improved mechanical properties. It has been discovered that the liquid state processing method is the most affordable and straightforward for processing MMCs out of all the existing ways. Primary processing, such as casting composite materials has its own restrictions on agglomerate formation and porosity. A metal matrix composite made of aluminum and aluminum oxide (Al2O3) has been chosen for the current investigation based on the literature review. A composite material including aluminum A356 and different percentages of Al2O3 (3%, 6%, 9%, and 12%) particles of 23�m size is chosen for the study. Using the SEM and EDAX test, the impact of these materials on the microstructural investigations is being investigated and the results indicates that uniform distribution of the reinforcement is difficult to achieve at higher percentages.

Effect of Y2O3 on thermophysical parameters and mechanical properties of Al-Al2O3 composites and compatibility with high temperature Al-Si alloys

Abstract Al-Al2O3 is a crucial encapsulation composite used in solar thermal storage systems. This study utilized Al and Al2O3 powders as raw materials, with Y2O3 serving as a sintering aid, to prepare Al-20Al2O3-xY2O3 composites (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 wt%) through the cold pressure sintering method. The latent heat, thermal conductivity, and bending strength of the Al-20Al2O3-xY2O3 composites were measured. The compatibility of the composites with Al-12 wt%Si alloys was analyzed. Furthermore, the relationships between thermophysical parameters, mechanical properties, compatibility, and microstructure were explored. The oxidation mechanism of Al and the wetting angle of the composites with Al-12Si were simulated using LAMMPS software. It was concluded that with an increase in Y2O3 content, the bending strength, thermal conductivity, and compatibility of the composites initially increased and then decreased. The Al-20Al2O3-0.2Y2O3 composite exhibited the least porosity, highest bending strength (76.32 MPa), and thermal conductivity (46.82 W/(m·K)). In compatibility testing, the diffusion distance of Si atoms was shortest (90 μm) in the Al-20Al2O3-0.2Y2O3 composite. Moreover, this composite had the largest wetting angle (88°) with the Al-12Si alloy, resulting in good compatibility between them.

Effect of Si3N4 on the in-situ synthetized non-oxide reinforcements in Al-Al2O3 composites under N2 atmosphere

Al-Al2O3 composite is widely used in high-temperature industry due to its excellent properties obtained through in-situ synthesis of non-oxide reinforcing phases. The effect of nitrogen source on the non-oxide reinforcing phases synthesized in-situ in the Al-Al2O3 composites at 1500 °C was investigated. The results show that when N2-gas is the sole nitrogen source, Al4O4C is the major reinforcing phase formed in the composite due to insufficient nitrogen amount provided. Through the construction of an Al@AlN core-shell structure and spontaneous nitrogen introduction by solid Si3N4 and N2-gas, higher amount of AlN mesophase is generated, and the complete transformation of Al to (Al2OC)1-x(AlN)x solid solution is successfully achieved. However, when Si3N4 content is excessive (i.e. Si/C mole ratio ≥ 1, where Si comes from solid nitrogen source Si3N4, C comes from phenolic resin binder), the stability of (Al2OC)1-x(AlN)x solid solution decreases, and more stable AlN-SiC solid solutions and SiAl4O2N4 are generated as reinforcing phases in the composite. This work provides meaningful information for the phase control of Al-Al2O3 composite at high temperature application.

Feasibility of using ground Al-Al2O3 composite powders in laser powder bed fusion

The reincorporation of residues in the productive cycle helps reduce CO2 emissions and non-renewable resources extraction. Therefore, the present work studies the feasibility of reincorporating an aluminum residue in the productive cycle by means of an additive manufacturing technique. In this context, other issues considered are the importance of aluminum alloys, the improvement of their properties by adding alumina making composites materials, and issues that must be overcome when printing parts by laser powder bed fusion using a mix of Al and alumina powders. This work evaluates the suitability of Al alloy - alumina composite powders obtained by grinding Al alloy chips from sawing. Laser power and scanning speed were varied until the designed samples were obtained. The findings show that is possible to use powder obtained by grinding Al chips in the laser powder bed fusion technique to obtain Al-Al2O3 composites which exhibits hardness of 226 HV ± 34.3.

Fabrication of Cu/Al–Al2O3 laminar composites using squeeze casting and roll bonding techniques: Evaluation of microstructure, mechanical properties and wear characteristics

The influence of Al2O3 whiskers addition on the microstructure, tensile, hardness, and wear characteristics of Cu/Al–Al2O3 composites were examined. The squeeze casting was used to fabricate Al–Al2O3 composites with different volume fractions of whiskers. Then, they were bonded to Cu layers. The microstructural and morphological examination were carried out by using SEM, XRD, and EBSD analyses. For the as-cast composites, the agglomeration of whiskers was observed which was then decreased by the following roll bonding process. For the roll bonded composites, the tensile strengths of composites were 210 MPa, 233 MPa, and 250 MPa For Cu/Al-(5 % vol) Al2O3, Cu/Al-(15 % vol) Al2O3, and Cu/Al-(25 % vol) Al2O3, respectively. The wear rate decreased versus volume fraction of whiskers which is correlated with the enhanced hardness of layers in composites. Less material loss and less debris were observed in composites with a higher volume fraction of whiskers.

Strain rate-dependent behavior of cold-sprayed additively manufactured Al–Al[formula omitted]O[formula omitted] composites: Micromechanical modeling and experimentation

Metal matrix composites (MMCs) fabricated by cold spray additive manufacturing (CSAM) are increasingly gaining attention as structural materials due to their rapid production and scalability. Herein, the failure behavior of CSAM Al–Al2O3 composites under quasi-static and dynamic compression was studied by an experimentally informed/validated 3D microstructure-based finite element (FE) model. The debonding mechanism was found to grow at a higher rate consequently dampening the particle cracking mechanism when the strain rate rises to dynamic regimes. The stress-bearing capacity of the particles plays a key role in enhancing the flow stress and elongation at failure of the CSAM composite under high strain rates due to the lower propensity of particle cracking. Eventually, the model was exercised to study the microscale failure progression in the material under elevated temperatures. For the first time in the literature, this study informs on the correlation between the microscale failure mechanisms and the mechanical performance of CSAM MMCs at the macro scale across strain rates and temperatures whose outcomes are applicable to the design of next-generation materials with a tailored performance.

Corrosion electrochemical behavior of metal matrix composites “Al-nano-Al<sub>2</sub>O<sub>3</sub>” IN 0.5M NaCl aqueous solution

The corrosion-electrochemical behavior of nanocomposites of the “aluminum-nano-aluminum oxide” system, formed by direct chemical interaction of molten aluminum with titanium nanooxide in an environment of molten alkali metal chlorides at temperatures above 700оC, has been studied. Nanoalumina crystals in the α-Al2O3 modification, uniformly distributed throughout the volume of the metal matrix, were detected by means of electron microscopy and X-ray diffraction. The corrosion rate in 0.5M NaCl, determined by the gravimetric method, decreases by 3–4 times when moving from initial aluminum to Al-Al2O3 composites, while the nature of corrosion changes from pitting to uniform and the corrosion resistance class from 3 (resistant) to 2 (very persistent). This is due to the formation of a denser single-phase hydroxide coating on the surface of the composite compared to a two-phase loose coating on aluminum. The corrosion potential is not affected by the incorporation of aluminum oxide nanoparticles into the aluminum matrix.

Passive and active oxidation of Al in the Al–Al2O3 composite refractory at high temperatures in air

The active and passive oxidation of Al in Al–Al2O3 composites was investigated in air at high temperatures. As fresh air impinged on the surface of the Al–Al2O3 composite sample, a thin Al2O3 layer was preferentially formed via passive oxidation of Al, which consumed most of the oxygen and lowered the local Po2 inside the sample. At low Po2, active oxidation of Al occurred and predominated in the interior transition layer, which further lowered the local Po2 to extremely low values within the non-oxide stability field. The local equilibrium PAlxOy generated by the active oxidation of Al reached a micro-positive pressure state and served as a gas barrier, hindering the inward diffusion of O2. The Po2 inside the composite was lowered by Al in the outer layers via a self-gettering process. Subsequently, Al4O4C and Al2OC-AlN solid solution were formed by both the direct reaction of Al(l) and the indirect reaction of AlxOy(g). After sintering in air, the Al–Al2O3 composite exhibited a functional gradient structure with a thin oxide layer and an interior non-oxide-reinforced corundum. A reaction mechanism model was established.

A Study on the Influence of Zr on the Strengthening of the Al-10% Al2O3 Composite Obtained by Mechanical Alloying

Al2O3 is a traditional strengthening phase in aluminum matrix composites due to its high hardness and melting point. At the same time, zirconium is an important alloying element for heat-resistant aluminum alloys. However, its effect on the structure and properties of Al-Al2O3 composites remains unexplored at present. In this work, the effect of the addition of Zr (5 wt%) on the microstructure and strengthening of the Al-10 vol% Al2O3 composite was investigated for the first time. Composite materials with and without Zr addition were obtained through mechanical alloying as a result of ball milling for 20 h followed by multi-directional forging (MDF) at a temperature of 400 °C. OM, SEM and XRD were used to study the microstructure and its parameters. The work showed that the use of mechanical alloying and MDF contributes to the formation of dense composite samples with a nanocrystalline microstructure and a uniform distribution of alumina particles. The addition of Zr contributes to a 1.4-fold increase in the microhardness and yield strength of a compact sample at room temperature due to the formation of Al3Zr (L12) dispersoids. It was been shown that the largest contribution to the strength of both materials comes from grain boundary strengthening, which is at least 50% of the yield strength. The resulting composites exhibit high heat resistance. For example, their compressive yield strength at 350 °C is approximately 220 MPa.

Micromechanical damage analysis of Al-Al2O3 composites via cold-spray additive manufacturing

3D micro-scale finite element (FE) models were developed to analyze the stress-state-dependent initiation and growth of failure of cold-sprayed additively manufactured (CSAM) Al-Al2O3 composites. Informed by experimental particle size distributions and porosity measurements, representative volume elements (RVEs) were generated by Digimat. Stress-state-dependent constitutive models for the Al matrix and Al2O3 ceramic particles were implemented by VUMAT subroutines in ABAQUS/Explicit FE solver. For the first time in the literature on metal–ceramic composites, the microscale failure mechanisms involving matrix ductile failure, particle cracking, and matrix/particle debonding were all quantified based on the crack volume fraction, the fraction of cracked particles, and the fraction of fully debonded interfacial nodes, respectively. The FE model was quantitatively and qualitatively validated by the experimental data for Al-46 wt% Al2O3 under quasi-static uniaxial compression. The validated model was used to investigate the effect of the particle content and size on the material behavior subjected to different stress states. The results revealed that the failure mechanisms are activated in a specified order across different stress states: I. matrix/particle debonding, II. particle cracking, and III. matrix ductile failure. The material ductility observed under compression/shear vanishes under tension due to the earlier activation of debonding and the faster growth (∼ 10 times) of the particle cracking mechanism. Additionally, it was shown that the particle size minimally affects the material strength and flow stress under shear which is likely related to the low load transfer effect through the interfaces. The novelty of this work stems from the provision of a better understanding of the stress-state-dependent evolution of failure mechanisms through a systematic quantification framework whose outcomes have implications for the design of better-performing Al-Al2O3 composites via control of the evolution of failure mechanisms and developing micromechanism-based constitutive models for CSAM metal–ceramic materials.

FLAKE POWDER METALLURGY APPROACH FOR PRODUCTION OF Al–Al2O3COMPOSITES WITH ENHANCED PROPERTIES

Flake Powder Metallurgy (FPM) is utilized for the processing of Al–Al2O3composites. The effects of contents of 1-[Formula: see text]m-sized alumina (0, 3, 6 and 9 vol.%) on the microstructure, hardness, porosity and wear behavior of these composites are investigated. The as-received aluminum powder particles are milled in a planetary ball mill for different time durations (0.5, 1, 1.5 and 2 h), and the resultant flake powders are characterized by sieving, SEM, optical microscopy and XRD to determine their particle size, morphology and grain size. Al flakes and different amounts of Al2O3powders are stacked into the mold cavity using a floating column filled with alcohol. Then the compacts are cold pressed at 750 MPa and sintered in a tube furnace at 655∘C for 60[Formula: see text]min. For comparison, reference samples from as-received aluminum powders are also fabricated. SEM studies showed a uniform distribution of alumina particles within the matrix of FPM-processed composites. These composites, despite their higher porosity, exhibited higher hardness levels and improved wear properties in comparison with the conventionally produced powder metallurgy (PM) counterparts. This is due to: (i) the special morphology of the flake powders that contributed to a more uniform distribution of alumina within the matrix and (ii) their smaller grain size due to work hardening that occurred during milling, which resulted in higher hardness values.

The Mechanical Properties of Aluminum Metal Matrix Composites Processed by High-Pressure Torsion and Powder Metallurgy.

Al-Al2O3 and SiC metal matrix composites (MMCs) samples with different volume fractions up to 20% were produced by high-pressure torsion (HPT) using 10 GPa for 30 revolutions of Al-Al2O3, and SiC and powder metallurgy (PM). The effect of the processing method of micro-size Al MMCs on the density, microstructure evolution, mechanical properties, and tensile fracture mode was thoroughly investigated. HPT processing produces fully dense samples relative to those produced using powder metallurgy (PM). The HPT of the Al MMCs reduces the Al matrix grain size and fragmentation of the reinforcement particles. The Al matrix average grain size decreased to 0.39, 0.23, and 0.2 µm after the HPT processing of Al, Al-20% Al2O3, and SiC samples. Moreover, Al2O3 and SiC particle sizes decreased from 31.7 and 25.5 µm to 0.15 and 0.13 µm with a 99.5% decrease. The production of ultrafine grain (UFG) composite samples effectively improves the microhardness and tensile strength of the Al and Al MMCs by 31-88% and 10-110% over those of the PM-processed samples. The good bonding between the Al matrix and reinforcement particles noted in the HPTed Al MMCs increases the strength relative to the PM samples. The tensile fracture surface morphology results confirm the tensile properties results.

Nanosize Al2O3 reinforcement in Si-rich aluminum MMC for enhanced tribological performance in engine components

Aluminum metal matrix composites are increasingly popular nowadays because of their wide range of uses. The low weight and excellent mechanical qualities, such as strength and hardness, of Al-Al2O3 composites make them useful in many fields, including automotive, aerospace, electronics, aeronautics, and military. Most of the engine components are made of aluminum-silicon alloys because of their excellent casting and forming properties. In engine components wear is a crucial parameter to be considered therefore in this investigation Al-Si alloy with varying percentages of V2O5 has been considered to develop the Al-Al2O3 composite and evaluate its tribological aspect. For composite development, a novel in-situ approach has been used with the help of the stir-casting method. The tribological behavior of the different composites was examined experimentally and studied with sliding distance, applied load, and the amount of reinforcement. Composites show a significant increase in hardness relative to the base alloy because of the generation of hard alumina particles within the melt. The wear behavior of in-situ Al-Al2O3 composites was studied using a pin-on-disc setup. In terms of COF and wear rate, the composite with a 1% addition of V2O5 performed better in the trial.

Nano-additive manufacturing of multilevel strengthened aluminum matrix composites

Nanostructured materials are being actively developed, while it remains an open question how to rapidly scale them up to bulk engineering materials for broad industrial applications. This study propose an industrial approach to rapidly fabricate high-strength large-size nanostructured metal matrix composites and attempts to investigate and optimize the deposition process and strengthening mechanism. Here, advanced nanocrystalline aluminum matrix composites (nanoAMCs) were assembled for the first time by a novel nano-additive manufacturing method that was guided by numerical simulations (i.e. the in-flight particle model and the porefree deposition model). The present nanoAMC with a mean grain size <50 nm in matrix exhibited hardness eight times higher than the bulk aluminum and shows the highest hardness among all Al–Al2O3 composites reported to date in the literature, which are the outcome of controlling multiscale strengthening mechanisms from tailoring solution atoms, dislocations, grain boundaries, precipitates, and externally introduced reinforcing particles. The present high-throughput strategy and method can be extended to design and architect advanced coatings or bulk materials in a highly efficient (synthesizing a nanostructured bulk with dimensions of 50 × 20 × 4 mm3 in 9 min) and highly flexible (regulating the gradient microstructures in bulk) way, which is conducive to industrial production and application.

Investigation of solid particle erosion behavior of Al-Al2O3 and Al-ZrO2 metal matrix composites fabricated through powder metallurgy technique

The proposed research article presents an experimental investigation of solid particle erosion wear of Al2O3 and ZrO2 ceramic oxide reinforced metal matrix composite developed via powder metallurgy method. Two different kinds of metal matrix composites, Al-Al2O3 and Al-ZrO2 were developed with different proportions (0, 2.5, 5 and 10 wt%) of micro-sized ceramic oxide reinforcement powders. Vickers Hardness (HV), experimental densities of sintered samples, XRD and EDS were evaluated for mechanical characterization of fabricated metal matrix composites. Solid particle erosion wear tests were carried out at impingement angles 30–90° at varying set impact velocities of 30–90 m/s on air-jet erosion wear test rig using tiny micro-sized Al2O3 powders as an erodent. Air–jet erosion experiments were conducted as per the G76 standard for study of the steady-state erosion wear. ANOVA test revealed that wt% of reinforced contents was a significant parameter followed by impact velocity. 5 wt% of ZrO2 was observed to be the best wt% of reinforcement of all the combination of fabricated composites.

Aluminum metal composites primed by fused deposition modeling-assisted investment casting: Hardness, surface, wear, and dimensional properties

Fused deposition modeling -based three-dimensional printing techniques, when merged with the investment casting process, is one of the most innovative techniques for developing functionally graded metal–matrix composites in high-performance industrial applications. In this study, Al–Al2O3 matrix composites have been prepared by the combined route of fused deposition modeling and modified investment casting processes. In the first step, the Al–Al2O3 particles have been reinforced into nylon 6 thermoplastics for the preparation of fused deposition modeling-based feedstock filaments (in two configurations: C1 (60% nylon 6–30% Al–10% Al2O3) and C2 (60% nylon 6–28% Al–12% Al2O3). In the next step, the investment casting patterns of the fused deposition modeling process of nylon 6–Al–Al2O3 composites were prepared. Furthermore, the investment casting has been performed by controlling the proportion of nylon 6–Al–Al2O3, the volume of pattern, the density of pattern, barrel finishing media weight, barrel fining time, and number of mold wall layers considering Taguchi L18-based experimental design. Finally, the functional aluminum matrix composites were subjected to testing to investigate average surface roughness ( Ra), deviation inside the cube, average wear, and average hardness. The study results have suggested that maintaining a higher proportion of Al2O3 in three-dimensional printed parts leads to higher Ra, higher dimensional deviation, and higher hardness of investment cast parts. On the contrary, solid patterns have provided low wear rates and low-density patterns resulting in increased wear rates in final investment casted products. Furthermore, the responses are optimized concurrently with the “technique for order of preference by similarity to ideal solution–Taguchi” technique while considering the analytical hierarchical process and entropy weights of significance.

Investigation of mechanical properties and tribological performance of Al-LSP and Al-Al2O3 composite

Purpose This study aims to develop the Al-Si-Mg metal matrix composite, reinforced distinctly with lime stone powder (LSP; 12% by weight) and Al2O3 (12% by weight), and compare their mechanical properties and tribological performance. Design/methodology/approach The composites are fabricated through stir casting process. In view of the previous work, the Al-LSP composite with LSP reinforcement (12 Wt.%) shows enhanced mechanical properties and tribological performance, as compared with other weight percentages. Findings Though the Al-LSP composite is less expensive, it shows similar hardness, tensile strength and specific strength, when compared with Al- Al2O3 composite. However, the Al-LSP composite exhibits significant enhancement of above three properties, when compared with Al-Si-Mg metal. The systematic factorial design of experiments is obtained through Taguchi OA [L9]. The tribological performance is estimated through wear rate (WR-mm3/m) and coefficient of friction (CF) by varying the operating parameters of sliding distance (SD), load (L) and sliding velocity (SV). According to ANOVA results, the optimal condition of WR for all the tested materials is L1SD3SV1. Further, the optimal condition of CF is L1SD1SV3 for Al-LSP and Al-Si-Mg metal, while L2SD3SV2 is for Al-Al2O3 composite. The regression equation predicts the measured experimental values within error band of ± 8 percentage. Originality/value A comparison of two composite materials (Al-LSP and Al-Al2O3) with same weight fractions (12%) shows almost same trend in both the mechanical and tribological testing process. However, the developed Al-LSP composite exhibited better properties than the Al-Al2O3 and Al-base. Therefore, Al-LSP can be suggested for automotive applications (i.e., connecting rod, cylinder liners, camshaft) and structural applications (such as frames, over hanging supports), without compromising in desirable original with properties of constituents in the new material, which is achievable for looking to the end uses.

In situ formation mechanism of spinel-like Al5O6N and plate-like Al7O3N5 in the two-step sintered Al–Al2O3 composites

A designed two-step sintering was implemented in the resin bonded Al–Al2O3 composites under nitrogen to get active AlN precursor, in which the sample was firstly heated at 580 °C for 8 h then at 1700 °C for 3 h. The introduction of active AlN precursor promoted the synthesis of reinforcements. XRD and SEM were employed to investigate the two-step sintered Al–Al2O3 composites. In addition to the preferentially formed Al2OC-AlN solid solution, plate-like Al7O3N5 and spinel-like Al5O6N were generated. Due to the higher content of active AlN from the nitridation of Al, Al7O3N5 nucleus was synthesized from solid-state reaction. Then, plate-like Al7O3N5 was obtained from liquid phase reaction and gas phase reaction. In the meanwhile, the AlN with lower content from carbothermal nitridation of Al2O3 reacted with Al2O3 to Al5O6N. In addition, gas phase reaction also contributed to the formation of spinel-like Al5O6N. And the reaction models were established in this paper.

Effect of Si3N4 mesophase on the formation of Al2OC-AlNss in resin-bonded Al–Al2O3 composites

In this study, we developed a novel method for synthesising Al2OC-AlNss using a solid nitrogen source: a Si3N4 mesophase. The two-step sintered Al–Al2O3 and Si3N4–Al–Al2O3 samples were prepared under an atmosphere of nitrogen to investigate the effect of Si3N4 on the formation of Al2OC-AlNss in resin-bonded Al–Al2O3 composites. The samples were investigated via XRD and SEM. The results indicated that the synthesis of Al2OC-AlNss with different morphologies was achieved via the Si3N4 mesophase, and its morphology was influenced by the source of AlN. Both Al2OC-AlNss and Al4O4C were formed in the two-step sintered Al–Al2O3 sample, whereas only Al2OC-AlNss was formed in the two-step sintered Si3N4–Al–Al2O3 sample. Induced by the AlN formed by the nitridation of Al, needle-like Al2OC-AlNss was generated. Compared to that formed by the nitridation of Al, more AlN nuclei were provided by the reaction between Si3N4 and Al. Subsequently, columnar and granular Al2OC-AlNss were formed. Furthermore, fibre-like Al2OC-AlNss was also generated via the VS and VLS mechanism. The reaction model was established in this study.

In situ formation mechanism of aluminum oxycarbonitride in the unoxidized zone of Al–Al2O3 composites

The Al–Al2O3 composites were prepared by fused alumina, α-Al2O3 micropowders, and metal aluminum powder. The samples with 3% carbon black (N330), 3% resin powder and α-Al2O3 micropowder, 10% α-Al2O3 micropowder were named S1, S2, and S3, respectively. They were oxidized at 1500 °C for 3 h in a box-type electric furnace, and then the unoxidized areas were analyzed by X-ray diffraction and scanning electron microscopy. It was found that the aluminum oxycarbonitride formed in situ during the oxidation resistance test inhibited further oxidation of S2. The in situ formation mechanism of aluminum oxycarbonitride in the unoxidized zone is believed to be 7Al + 3Al3C4 + 12AlN + 4Al2O3 = 12Al3CON, which is also verified and proven by XRD, SEM and EDS in this work. The oxidation depth of S2 is 46.7% lower than that of S3. Sample S2 hardly has any linear change after fired at 1500 °C × 3 h in coke, which benefits to improve the volume stability and prolongs the service life. Among the three batches, S2 exhibits the minimum creep rate, from 0% to 0.026% at 1500 °C, and the HMOR at 1500 °C in a N2 atmosphere of S2 is 58 MPa. The Al–Al2O3 composites combined with resin strengthened by in situ formed aluminum oxycarbonitride give the composites excellent high-temperature strength owing to the fiber-intersected reinforced microstructure of Al3CON crystals at high temperature. In the Al–C–N–O system, it was found that the general formula of aluminum oxycarbonitride is expressed by Al4n+m(C,O,N)3n+m, and the (n, m) values are (0, 3) for Al3CON.