Ryo Inoue

• Doctor of Engineering
• Professor (Associate) at Tokyo University of Science

This study presents a comprehensive quantitative investigation into the material properties and damage behavior of unidirectional carbon fiber reinforced plastic laminates with ply discontinuities. Laminates with varying resin gap lengths were evaluated. In situ edge observations and X-ray computed tomography were employed to assess the damage proc...

The oxidation and recession of carbon-fiber-reinforced ultrahigh-temperature ceramic matrix composites (C/UHTCMCs) fabricated via reactive melt infiltration (RMI) using Zr-Ti alloys with three different compositions are evaluated via an arc-jet tunnel test at temperatures above 2000 °C for 60 s. Thermodynamic evaluations show that the recession of...

To achieve Si‐free refractory ceramic matrix composites exposed to an oxidizing atmosphere at approximately 2000°C, a Ti–Zr–Mo ternary alloy melt‐infiltration (MI) method was developed for the production of carbon fiber‐reinforced refractory high‐entropy ceramic matrix composites (C/RHECs), with high‐entropy carbides serving as the matrix. This app...

The relationship between morphology (grain-size order) and mechanical properties of Al x CoCrCuFeNi (x = 0.3 and 1) was evaluated. Both alloys were prepared using the arc-melting method. Crystal structures with x = 0.3, face-centered cubic (FCC), and body-centered cubic (BCC) structures were observed for x = 1, the typical crystal structures of Al...

Carbon-fiber-reinforced epoxy-matrix composite (CFRP) laminates with thin plies have strong damage-resistance properties compared with standard prepregs. The static and fatigue tensile fracture behavior of cross-ply CFRP laminates with thin plies should be further studied to establish the applicability of thin-ply prepregs for industrial structures...

The mechanical reliability of products must be assured for scaling up and production of complex‐shaped components by spark plasma sintering (SPS) of spray‐dried granules. The evolution of morphologies of pores and defects, which control the mechanical strength, is investigated by using synchrotron X‐ray multiscale tomography during SPS of alumina g...

In the present study, we performed three-dimensional observation and analysis of strain distribution for all-oxide ceramic matrix composite (CMC) using X-ray computed tomography (X-CT) and digital volume correlation technique (DVC). For testing, uni-directionally (UD) reinforced oxide matrix CMC was used for model material. Mechanical properties of...

The mechanical reliability of products must be assured for scaling up and production of complex-shaped components by spark plasma sintering (SPS) of spray-dried granules. The evolution of morphologies of pores and defects, which control the mechanical strength, is investigated by using synchrotron X-ray multiscale tomography during SPS of alumina g...

The heat resistance of carbon fiber-reinforced ultra-high-temperature ceramic matrix composites (C/UHTCMCs) was characterized by arc-wind tunnel testing with heat fluxes of 2, 4.54, and 6.68 MW/m². C/UHTCMCs were fabricated via Zr-Ti binary alloy (Zr-20at%Ti, Zr-64at%Ti, Zr-80at%Ti) melt infiltration. The thickness and weight changes of the specime...

The uniaxial die compaction and sintering is an important industrial production method for metal and ceramic components. While submicron- and nano-sized powders are finding increasing use for making dense materials with finest grain sizes, the uniformity of microstructure, and then, the reliability of the products depend on the heterogeneity in pow...

Carbon fiber-reinforced ultra-high temperature ceramic matrix composites (C/UHTCMCs) were fabricated via Zr-Ti alloy melt infiltration (Zr-Ti MI) using carbon-carbon composite (C/C) preforms and alloys with three different compositions. Alloys were successfully infiltrated into C/C to form solid solutions of TiC and ZrC, with melting temperatures >...

In this study, the influence of laser process parameters on the observed geometrical imperfections in a lattice structure were investigated experimentally. The imperfections were measured by using the X-ray CT machine, and the compressive response of lattice structures fabricated by our in-house metal 3D printer based on the powder bed fusion (PBF)...

Using arc melting, a novel rare-earth silicide, middle entropy Yb-Gd-Ti-Si, was fabricated for high-temperature material applications. The oxidation behavior of the Yb-Gd-Ti-Si was evaluated through oxidation tests conducted at 1200 °C for 1, 2, 4, and 8 h in air. The oxidation rate at 1200 °C was almost the same, regardless of the addition of Ti....

Oxide fiber-reinforced oxide matrix composites (Ox/Ox-CMCs) were fabricated by vacuum-assisted impregnation and pressureless sintering using a high-yield alumina precursor. The Ox/Ox-CMCs were sintered at 1100 and 1200 °C for 2 h. SEM and X-ray CT revealed that in both cases the matrix formed successfully within and between the woven fabrics. Vicke...

Three‐dimensional networked porous carbons (TNPCs) exhibit unique structures, and the relationship between the Young's modulus and relative density does not follow the conventional relational expression proposed by Gibson and Ashby. In this study, image analysis for TNPC models developed by reconstructing cross‐sectional images obtained via X‐ray c...

Carbon fiber-containing refractory high-entropy ceramic matrix composites (C/RHECs) were fabricated through a reaction with carbon powders, transition metal carbides, and Zr–Ti alloys as a novel heat resistant material used for components of hypersonic vehicles cruising at Mach 7–10. With the infiltration of alloys at 1750 °C into a composite prefo...

Carbon-fiber-reinforced ultrahigh-temperature ceramic (C/UHTC) matrix composites are an attractive candidate for fabricating various hot structures. The present study aimed to establish a Si-free Zr-Ti melt-infiltration method for fabricating C/UHTC matrix composites. To achieve this, the wettability of Zr-Ti alloys on carbon and their reactivity t...

Herein, we prepared 3D-networked porous carbon materials (TNPCs) (porosity ≈ 70%, average pore size ≈ 10 μm, density ≈ 0.37 g cm–3) composed of glassy carbon via pyrolysis of porous phenolic precursors. A compressive test for TNPCs shows that the Young’s moduli and compressive strength of TNPCs ranged from 0.7 to 1.5 GPa and 11 to 30 MPa, respectiv...

Micro‐speckle patterns were fabricated using α‐Al2O3 and SiC micro‐particles for in‐plane strain distribution measurement at temperatures up to 1500 ℃ using an ultra‐violet high temperature observation system (UV‐HTOS) combined with a digital image correlation (DIC) technique. The experimental results showed that the measured mean surface strains o...

To improve the oxidation behavior of Yb-Gd-Si, 0.5 and 1 at% of Ti-containing Yb-Gd-Si (denoted as YGTS-0.5 and YGTS-1, respectively) were fabricated by arc melting. The oxidation behaviors of both YGTS specimens were evaluated by oxidation tests performed in a temperature range of 600–1200 °C for 1, 2, 4, and 8 h in air. Additionally, thermogravim...

The degradation behavior of Yb- and Gd-based ternary silicides (YbGdSi) was evaluated in Ar, 50 vol%air-H2O (air-H2O), and 100vol%H2O (steam) environment and compared with the results obtained in a previous study conducted in air environment. Heat exposure at 1200 °C for 1, 2, 4, and 8 h was carried out in addition to thermogravimetric analysis up...

This study sought to examine the relationship between the degradation mechanism, thermal stress, and crack propagation behavior in environmental barrier coating (EBC) systems. An EBC system composed of a mullite topcoat (TC), Si‐bond coat (BC), and SiC substrate was prepared by atmospheric plasma spraying. Heat exposure tests were conducted to eval...

To further enhance the thermoelectric (TE) capability of Mg- and Mn-silicides in order to realize a practical TE power generator (TEG), sufficiently low resistance ohmic contacts at the interface between the electrode material and the Mg- and Mn-silicides are needed. In this chapter, we report a method to obtain thermally stable electrodes on Mg- a...

In this study, the influence of laser process parameters on the observed geometrical imperfections in a lattice structure were investigated. the Imperfections were measured by using the X-ray CT and SEM machines. Here, the imperfections include the ovalization of the cross-section, offset of the central axis and inner void. These imperfections coul...

Ytterbium (Yb)- and silicon (Si)-rich ytterbium silicides (Yb5Si3, and Yb3Si5) were successfully fabricated by arc-melting and heat treatment. The degradation behavior of both silicides was evaluated by means of oxidation tests under three different conditions: Air, air-H2O, and steam. The results showed that the degradation of these Yb-silicides i...

In this paper, a heat transfer enhancement technique is proposed using porous materials with micropores. To eliminate the binding process between a heating surface and a fabricated porous body, the porous material is directly fabricated on a copper heating surface using a coating method. The starting material is liquid state. After coating and curi...

A ternary alloy with an Yb-Gd-Si composition was designed using thermodynamic calculation software. The ternary alloy with two different steady-state phases (Yb:Gd:Si = 25:18:57 and 19:23:58 at%) was successfully fabricated using arc melting. Oxidation tests were carried out at 1200 °C for 1, 2, 4, and 8 h in air. Thermogravimetric and microstructu...

The thermal protection performances of polymethylmethacrylate-impregnated porous carbon ablators with three different densities were examined in an arc wind-tunnel test. The more impregnated ablator exhibited significantly higher exhaust gas pyrolysis and heat absorption, which improved the recession resistance, the gas-blocking effect for convecti...

Owing to their large surface area and capillary effect, porous materials are highly desired for heat-transfer applications. In this study, we investigated the evaporation behavior of a water droplet on porous epoxy resin with a three-dimensional network structure. As the material existed in the liquid state before sintering, it could be easily conv...

In order to clarify the long-term durability of CFRP strands, tensile and fatigue tests at room and elevated temperatures were conducted. Firstly, tensile tests were performed under several temperature conditions from 23 to 250 ℃. The results showed that ultimate tensile strength of CFRP strands are dependent on temperature and superior to conventi...

In this study, the compressive response of lattice structures fabricated by SLM technology were investigated effects of observed geometrical imperfection on the mechanical properties (initial stiffness and plastic yield strength) of the structure were discussed. The cross-section of the inclined strut in a lattice becomes ovalization which is due t...

SiC/SiC composites are expected to be used as materials for the next generation aircraft engines. The purpose of this study is to improve the thermal performance of SiC/SiC composites by MI method. In the conventional MI method, Si is infiltrated into the composites, however, Si remains in the matrix. In this study, the Si-Ni-Ti alloy was infiltrat...

In order to ensure the safety and reliability in research and development of high temperature structural materials, it is important to develop an experimental technique to visualize the deformation distribution at elevated temperature for understanding deformation and fracture mechanisms quantitatively. In the present study, the principle of stereo...

All-oxide composites were fabricated by vacuum impregnation and pressure-less sintering. The mechanical properties of the all-oxide composites with the matrix densified by fine alumina particles and high yield of alumina precursors were investigated. Dense matrix was formed with uniform Vickers hardness independent of the location in the composite....

In order to investigate the effect of ply thickness and stacking order on the mechanical properties of CFRP laminates, five different laminates were prepared using two different types of prepregs with different layer thicknesses. All the laminates were cross-ply and only the stacking order was changed. Static tensile tests, tensile fatigue tests, a...

The pulse thermography (PT) technique was applied to the detection of the delamination of a multi-layered coating system composed of mullite/Si onto a reaction-bonded SiC substrate. The potential evaluation was carried out in order to detect internal delamination in multi-layered material system. Moreover, the observation of the cross sections and...

Recent studies on carbon fiber-reinforced ultra-high temperature ceramic matrix (C/UHTC) composites fabricated by hot-pressing, chemical vapor infiltration, polymer impregnation and pyrolysis, and melt infiltration (MI) are reviewed. Various efforts have been made to improve these preparation processes and to combine two or more of these because th...

The oxidation and recession of four plain weave carbon fiber reinforced ZrB 2 -SiC-ZrC composites with different matrix compositions were compared with those of a plain weave carbon fiber reinforced ZrB 2 -SiC matrix composite. These composites were fabricated using a silicon melt infiltration method. The composite with the higher ZrC content also...

A mullite/Si multilayer coating was deposited on a SiC substrate using atmospheric plasma spraying. Mud cracking of the protective surface mullite layer was examined using a high-temperature observation system (HTOS). In-plane surface strain distributions were also measured using the digital image correlation (DIC) method. The experimental results...

In this study, a fabrication procedure for a porous carbon material with different pore diameters was successfully performed; the fabrication procedure uses phenol monolith as a precursor material. This porous carbon material has many applications, for example, as a component of ablative thermal protection systems. The phenol monolith was obtained...

Dense composites consisting of copper and ZrW2O8 (ZrWMoO8) with negative thermal expansion (NTE) properties were fabricated at low temperature by using spark plasma sintering (SPS). X‐ray diffraction (XRD) analyses suggested that the Cu‐ZrW2‐XMoxO8 and Cu‐ ZrWMoO8 composites were thermally stable at 773 K and 673 K. The coefficient of thermal expan...

In the previous study, three-dimensionally networked porous carbon (TNPC) was used as a preform of the ablator. As a result, recession resistance was same level with that of the conventional one. Oxidation and sublimation of carbon were considered as causes of damage. Therefore, it is considered that recession resistance can be improved by dispersi...

Porous carbon materials have been expected as heat protection materials, fuel cells, and space craft structures. In this study, a porous carbon material having a monolith structure was prepared using a spinodal decomposition mechanism. Compression testing and image-based modeling using tomography were also carried out, and elastic properties of car...

The oxidation behavior and oxidation mechanisms of monolithic ZrB2 and particulate-ZrB2 matrix composites were reviewed. Dispersion of SiC particles into ZrB2 was found to be an effective way to prevent extensive oxidation. However, the formation of a SiC-depleted layer can become a critical problem because it can lead to spallation and delaminatio...

Inter- and intragranular SiC-nanoparticle/Mg2Si composites were fabricated by plasma activated sintering, and the fracture toughness and thermoelectric properties were characterized. The toughness of the intragranular composite was 60% higher than that of pure Mg2Si. The electrical conductivity became lower compared with pure Mg2Si, however, it was...

Si-rich ytterbium silicide was fabricated by through an arc-melting technique for applying use as a bond coat material in an environmental barrier coating system. Evaluation of its potential was accomplished through oxidation tests in dry air and an inert atmosphere. The experimental results showed that the changes in weight and morphologies of ytt...

A porous carbon material with a three-dimensional network and open-cell structure was applied to preform new lightweight ablators. The materials impregnated into the porous carbon were polyimide, phenol, and poly(methyl methacrylate). To evaluate the performance of the ablators, their thermal response and recession resistance were evaluated using a...

There is an urgent need to develop new methods for assessing strain in polymers without damaging the material’s intrinsic properties. The disadvantages of current methods include: high costs; impregnation of the polymer with bulky mechanical devices; inability to measure in several dimensions; and interaction with electromagnetic radiation. In this...

Short and plain-woven continuous carbon fiber-reinforced ZrB2-SiC-ZrC (Csf/ZSZ and Cpw/ZSZ) matrix composites were fabricated by a Si melt-infiltration process for application to thermal protection systems (TPSs). The fracture toughness of both composites was improved compared to those of ZSZ ceramics. The effects of the thermal properties, volume...

This chapter examines how the compressive properties of three‐dimensionally networked porous carbon material (TNPC). The Young's modulus and compressive strength of TNPC under uniaxial compressive loading were 1.34 GPa and 26.9 MPa, respectively, which are quite higher than those of the conventional carbon foams. The results showed that these ablat...

We describe the fabrication of in-plane randomly oriented short carbon fiber-dispersed ZrB2-SiC (Csf/ZS) and ZrB2-SiC-ZrC (Csf/ZSZ) matrix composites with different slurry compositions using Si-melt infiltration (Si-MI). We also carried out microstructural observations, measurements of thermal conductivity, and oxyhydrogen torch oxidation tests. Mi...

SiC fiber reinforced SiC matrix (SiC/SiC) composites are considered as an attractive candidate for the component of next generation gas turbine engines. Generally, mechanical properties of SiC/SiC composites are strongly influenced by interfacial properties between fiber and matrix because load transfers from matrix to fiber must occur through the...

Porous materials are expected to utilize heat protection materials, adsorption / desorption materials, electrodes, etc. Generally, mechanical, thermal and other properties of them are changed by pore size, pore shape and porosity. Therefore, it is necessary to control the structure of the porous material. In the present study, phenol monolith, whic...

Porous carbon materials are expected for applying for heat-resistant lightweight structural materials in aerospace field because they have high strength relative to their low density and heat resistance. In the present study, we studied three-dimensionally networked porous carbon materials (TNPCs) for applying ablators, which are used thermal prote...

Thermal Protection Systems (TPS) is used to protect the spacecraft from heat generated during re-entry. The ablator is a typical example of TPS, which is generally composed of short carbon fiber and a resin. Thermal protection is realized by thermal decomposition of the resin and gas, carbonized layer In the present stydy,we developed new light wei...

The oxidation behavior of four ZrB2-SiC-ZrC compositions with varying ZrC contents (20, 34, 50, and 64 vol.%) was compared to that of ZrB2-SiC. The ceramics were oxidized at 1700°C in an oxygen-hydrogen torch environment. The liquid oxide on the ZrB2-SiC sample came off from the surface under such an environment. In contrast, the all ZrB2-SiC-ZrC s...

The initial oxidation behavior of ZrB2–SiC–ZrC (ZSZ) composites above 2000 °C after the initial ∼5–10 s was examined by an electric heating system. The morphology of the oxide layer was shown to depend on the ZrC content. Volume expansion during the conversion of ZrC to ZrO2 contributed to the morphology of the surface oxide layer. Above 2000 °C, t...

This chapter discusses how a 3Al2O3.2SiO2/Si/SiC environmental barrier coating (EBC) system was fabricated by the atmospheric plasma spray process. Microstructural characteristics and mechanical properties after heat exposure at 1300Υ for 1, 50, and 100 h were investigated. The Young's modulus and hardness of as-deposited and heat-exposed mullite E...

The mechanical properties of as-sintered and heat-exposed polycrystalline Mg 2 Si were investigated. The strength of the as-fabricated specimen depends on the surface flaws. After heat exposure in Ar atmosphere, oxidized products formed, mainly consisting of MgO. The strength increased after the heat exposure, and the surface oxidation product fill...

Fracture toughness tests for short carbon fiber-dispersed SiC matrix (SCF/SiC) composites fabricated by means of the silicon melt infiltration (MI) process have been carried out under mode I, mode II and mixed I/II mode loading conditions. A Brazilian disk specimen was used for the mixed-mode fracture toughness test. The results showed that the fra...

Rapid oxidation testing for monolithic ZrB2 and ZrB2–SiC binary composites with different SiC contents (0–30 vol%) was performed using an electric heating system above 2000 ℃. The system used in this study achieved the high heating rate of 250 ℃/s. The experimental results showed that the morphologies of the oxidized specimens depended strongly on...

The interfacial strength between carbon fiber and phenolic resin is studied using molecular dynamics simulations to demonstrate that carbon fiber-reinforced carbon matrix composites (C/C composites) have improved tensile strength. Simulations are performed using two carbon fiber models, one of which has only carbon atoms and the other has carbon at...

In order to prevent the formation of SiC-depleted layer in SiC particle dispersed ZrB2 matrix (ZS) composites, various attempts have been done. The authors reported that addition of ZrC particles is effective to reduce pore formation beneath surface protective scale. In order to apply ZrB2-based composites for structural components, improvement of...

Magnesium silicide (Mg2Si) is a promising thermoelectric(TE) material with the advantages of lightweight, abundance of its constituent elements in nature, and high power generation efficiency at about 873 K. This material is expected to apply automobile application to reduce waste heat, however improvement of mechanical properties is required for p...

Porous carbon material was derived from phenolic resin mixture by polymerization induced phase separation based on the spinodal decomposition. We prepared phenolic-based monolith based on benzenenesulfonyl chloride, sodium carbonate and ethylene glycol. In this study, the effect of composition of resin mixture, curing time and viscosity of phenolic...

In this study, we present a potential method to predict the highest surface temperature reached during the heating by Raman analysis for CFRP ablator, which is commonly used in aerospace fields as a material of thermal protection system. The specimens are heated using various treatments such as static heating and dynamic heating by arc jet in inert...

The oxidation behaviors of four compositions of ZrB2-SiC-ZrC and one composition of ZrB2-SiC were studied at 1700 °C in air and under low oxygen partial pressure. Volatility diagrams for ZrB2-SiC-ZrC and ZrB2-SiC were used to thermodynamically elucidate the oxidation mechanisms. SiO2 and ZrO2 layers formed on the surfaces of ZrB2-SiC-ZrC and ZrB2-S...

ZrB2-SiC-ZrC (ZSZ) ternary composites of four differing compositions were fabricated by spark plasma sintering (SPS). The effect of the ZrB2/ZrC ratio on the oxidation behavior was examined by thermogravimetric (TG) analysis and microstructural observations. In addition, in-situ observation above 1500°C was performed using a high-temperature observ...

The interfacial strength between carbon and phenolic resin is studied by using molecular dynamics simulations in order that carbon reinforced carbon matrix composites (C/C composites) has better the tensile strength. Simulations are performed by two carbon fiber models, one of which has only carbon atoms and the other has carbon atoms and some fluo...

C/ZrB2-SiC-ZrC (C/ZSZ) composite is one of the candidate materials for thermal protection systems of aerospace application. This heat-resistant material indicates excellent ablation resistance at high temperature above 1700°C. In the present study, C/ZSZ and C/ZrB2-SiC were fabricated by melt infiltration of Si. ZSZ, ZrB2-SiC and ZrC-SiC were also...

Porous carbon materials are potentially applicable for light-weight applications such as advanced spacecraft structures. One of the problem is the lack of the investigation about microscopic stress state during a fracture process. In this study, stress analysis of a porous carbon material, which has three-dimensionally networked structure, was perf...

SiC fiber-reinforced SiC matrix (SiC/SiC) composites have been expected for turbine blades in the next generation aircraft gas turbine engine. Environmental barrier coating (EBC) is also needed to protect the SiC/SiC turbine blade from surface recession in high temperature water vapor atmosphere. In addition, damages of the coating caused by foreig...

In the present study, we developed new light weight ablator using three dimensionally networked porous carbon (TNPC) material. Acrylic resin was impregnated into TNPC. Evaluation of performance of developed ablator was carried out using an arc wind tunnel. Thermal response and recession resistance of developed ablator were examined by arc wind tunn...

In-situ observation during heating and cooling was carried out in order to understand damage evolution behavior of environmental barrier coating system at high temperature. In addition, in-plane deformation was measured using digital image correlation (DIC) technique. Quality of acquired image was not changed up to 1200°C. The results of strain dis...

ZrB2-SiC-ZrC (ZSZ) ternary composites of four differing compositions were fabricated by spark plasma sintering (SPS). The effect of the ZrB2/ZrC ratio on the oxidation behavior was examined by thermogravimetric (TG) analysis and microstructural observations. In addition, in-situ observation above 1500°C was performed using a hightemperature observa...

Mg_2Si (Magnesium silicide) has been expected as the materials used for thermoelectric (TE) technologies due to lightweight, abundance of its constituent elements and its non-toxicity. Because TE conversion devices are subjected to various thermo-mechanical loadings during operation, evaluation of the mechanical properties of Mg_2Si is necessary fo...

ZrB_2-SiC-ZrC(ZSZ) is known as one of ultra-high temperature ceramics (UHTCs) composite materials. In this study, four different composition of the ZSZ and ZrB_2-SiC were fabricated by spark plasma sintering. The specimens were oxidized at 1700℃ for 10 min in two different oxygen partial pressure. After the oxidation tests, SiO_2 and ZrO_2 were for...

Fracture behavior and toughness of short carbon fiber-dispersed SiC matrix composite fabricated by silicon melt infiltration process has been studied under I+II mixed mode loading conditions. Fracture tests are carried out using notched disk specimen. The fracture toughness of the composite measured in all the applied loading modes is in the range...

Measurement of mode I fracture toughness of in-plane random oriented short carbon fiber-dispersed SiC matrix composite fabricated by melt infiltration process has been carried out. Fracture toughness (KIc)(KIc) measured using a Brazilian disk specimen is ~3.5−4.1MPam, which is comparable to those of monolithic engineering ceramics. The measured tou...

Tensile and fracture tests for dried nacre were carried out. Dried nacre fractured in a brittle fashion, but its toughness perpendicular to the plane of the plate was 10 times greater than that of natural CaCO3. A simple model in which plates interlock was proposed based on the observations of fracture behavior and the fractured surface. The contri...

Among many kinds of “nano-laminar” composites inspired by the brick and mortar structure of nacre in mollusk shells, a bulky, dense and ceramics–base composite has been a missing piece despite its importance. Here we report that such a composite with a submicron-order layered structure can be fabricated by a simple method, sintering aligned flake-l...