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Aluminum matrix composites with various particle reinforcements have been experimentally tested to evaluate their fracture toughness. The experimental results have been compared with the fracture toughness estimates using the Hahn–Rosenfield model. It is observed that the Hahn–Rosenfield model has a validity range for reinforcement particle sizes of 5–10 μm. A modification to this model has been developed for estimating the fracture toughness of the metal matrix composites with larger particle reinforcements. The validity of the modified model has been experimentally tested. There has been a close agreement between the experimental results and the predicted toughness using the modified fracture model.

TiNi/CFRP composites have been fabricated by hot-pressing at a temperature of 180 °C. The CFRP layers were stacked with the carbon fibers at angles of 0°, 30°, 60° or 90° relative to the tensile direction. The fracture behavior was studied using notched specimens, which act as one-dimensional AE sources during tensile testing, to determine the fracture mode of the composites. Detection of strong Lamb waves shows that fracture in TiNi/CFRP composites with a 0° stacking configuration is mostly due to fiber breakage, which accounts for the high tensile strength of this configuration. In contrast, specimens with high stacking angles mainly fail by matrix cracking, with the production of weak Lamb waves, resulting in lower tensile strengths.

TiNi fiber impregnated CFRP composites have been fabricated by hot-pressing at a temperature of 180 °C. The host material (CFRP) layers were stacked with the carbon fibers at angles of 0°, 30°, 60° or 90° relative to the tensile direction. The tensile strengths and Young's moduli of the composites are found to depend strongly on the stacking angle of the carbon fibers. Their values decrease as the stacking angle increases from 30° to 90°. Pores and/or voids are found to congregate near the embedded TiNi fibers and their amounts increase proportionally with the stacking angle of the carbon fibers. The effect of strengthening by stacking angle of carbon fibers was studied by an AE technique during tensile testing.

The focus of this work is the thermomechanical characterization of pre-strained TiNi fiber impregnated CFRP composites. TiNi/CFRP composites were fabricated by hot-pressing at a temperature of 180 °C. The compressive recovery force induced by thermomechanical actuation of TiNi fibers depends on the pre-strained level. The shrinkage strain due to the thermomechanical response of the composites increased with increasing pre-strain level and number of impregnated TiNi fibers. Transverse cracks which formed at 90 ° to the CFRP layers under tensile loading could be healed by the compressive recovery force introduced by pre-strained TiNi fibers when electrically heated.

The ductile fracture process consists of void nucleation, growth and coalescence. The whole ductile process can be divided into two successive steps: (I) the initial state to void nucleation, followed by (II) void growth up to void coalescence. Based on this suggestion, resistance to ductile fracture could be divided into the resistance to stage I and stage II, and accordingly the whole fracture toughness could be regarded to be due to contributions from stages I and II. The fracture toughness contributed from the two steps is, respectively, denoted as void nucleation-contributed fracture toughness and void growth-contributed fracture toughness. The effect of plastic pre-strain on the fracture toughness of ductile structural steels under static and dynamic loading (4.9 m/s) within the ductile fracture range was evaluated by summing contributions due to void nucleation-contributed and void growth-contributed fracture toughness. The effect of strain rate on fracture toughness was also investigated by the same means. The results show that both plastic pre-strain and high-speed loading decrease the void nucleation-contributed fracture toughness while their effects on the void growth-contributed fracture toughness depend on the variations in strength and ductility. Moreover, fracture toughness of structural steels generally decreases with increasing strain rate.

The effect of treating the surface of TiNi fiber by acid etching on the interfacial adhesive strength between the TiNi fiber and the CFRP matrix is investigated. For acid etching of the TiNi fiber, acid solutions of 36% HCl, 15% HNO3, 97% H2SO4, and 3% HF+15% HNO3 were used. The composites were fabricated by curing at 180 °C for 2 h using hot-pressing. The interfacial adhesive strength between the embedded TiNi fiber and the CFRP matrix was evaluated by a pullout test. It was found that surface treatment of the TiNi fiber by acid etching improved interfacial adhesive strength.

In the 2nd Science and Technology Basic Plan (2001–2005), the area of nanotechnology and materials is designated one of the four prioritized areas in funding. Following this plan, Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Ministry of Economy, Trade and Industries (METI), the main funding ministries, and their organizations, Japan Society for the Promotion of Science (JSPS), Japan Science and Technology Agency (JST), National Institute for Materials Science (NIMS), RIKEN, New Energy and Industrial Technology Organization (NEDO), and National Institute of Advanced Industrial Science and Technology (AIST) promotes their research programs. Besides, in order to promote interdisciplinary, interorganizational, and international collaboration of researchers, Nanotechnology Support Project (NSP) was started by MEXT in 2002. The project has two missions: informational support and common use facility support. Nanotechnology Researchers Network Center of Japan is responsible for informational support, and 14 universities and national research institutes are responsible for common use facility support.

Adaptive composites, which consist of carbon fiber reinforced plastics (CFRP) and shape memory alloy (SMA) wires, have attracted much attention recently in the aerospace industry, etc. In the fabrication of such adaptive composites, CFRP and SMA wires must be cured at specific temperatures, either at 130 or 180 °C depending on the kind of matrix resin used. Since the curing temperature is much higher than the As (reverse transformation start) temperature of SMA, inconvenient special fixture jigs had to be used to keep SMA wires in the martensitic phase during the curing process, and thus restricted the shape and size of smart composites. Recently the present authors developed a new method for fabricating adaptive composites without using such fixture jigs. Although the method could be used for the curing temperature of 130 °C, it could not resolve the problem of the curing temperature of 180 °C. In the present paper we present a newer method, which has overcome the problem of the curing temperature of 180 °C by utilizing heavily cold-drawn ultrathin wires and low temperature heat-treatment.

This paper describes an application of laser techniques for the detection of acoustic emission (AE) signals at elevated temperature. The AE signals from an Al2O3 plasma sprayed coating on a SUS304 substrate were detected using four laser Doppler vibrometers during thermal cycling between 1000 °C and room temperature. The event location and the fracture mode of each AE could be determined due to the benefit of the laser techniques, non-contact measurement and absolute value measurement of surface velocity. This approach revealed the advantage and the disadvantages of the application of laser techniques for AE measurement in high temperature environment.

With the aim of the applications for smart composite, the influence of cold drawing on the shape memory effect and mechanical properties of Ti-49.5at%Ni and Ti-50at%Ni was investigated systematically. It was found that the reverse transformation temperatures increased significantly, while the martensitic transformation temperatures decreased with increasing amount of cold drawing. Both the temperature range for reverse and martenistic transformations became larger with increasing amount of cold drawing. A recovery strain above 2% and a recovery stress up to 300MPa can be obtained in cold drawn wires. A two-way shape memory effect was observed in as-cold drawn TiNi wires. These results indicate that cold drawn TiNi wires have many unique shape memory properties which can be applicable for smart composites.

The shape memory characteristics of cold-worked TiNiNb alloys were investigated for developing shape memory alloy/carbon fiber reinforced plastics hybrid composites for damage suppression even at ambient temperature. An alloy with very wide transformation temperature hysteresis (Ms 130 C) was developed, and the above composites were fabricated using it.

The static fracture toughness K IC and dynamic fracture toughness K Id of SN490, its pre-strained steel, and its welding heat affected zone were measured. K IC tests were conducted according to the ASTM standard, and K Id tests were carried out on an instrumented Charpy impacting machine. The experimental results were used to determine the effects of welding thermal cycle and cold working. It was found that both welding heat input and cold working are harmful to the fracture toughness of SN490 steel under both static and dynamic loading. The deleterious effects are serious under static loading. The detrimental effect of welding heat input during submerged arc welding was found to be more significant than that of the 10% plastic prestrain.

The effects of cold-working and subsequent low temperature heat-treatment on transformation temperatures and recovery strains were studied for heavily cold-drawn Ti–Ni. Consequently, the reverse transformation temperatures were found to increase further by the heat-treatment. The reason for the effect and how to use it in practical applications are fully explained.

Evaluation of microcracking behavior, among other nondestructive evaluations, is important for understanding the fracture of materials and improving their fracture resistance. This paper deals with the principle of the inverse problem analysis of acoustic emission (AE), the method of analyzing the moment tensor of microcracks developed by the author et al., and examples of the method's application. The paper goes on to introduce the concept of the smart materials and structural systems that perform nondestructive evaluation on their own and function to repair and restore defects. The paper also overviews the present state of research and development.

This paper describes acoustic emission (AE) measurement at elevated temperature by laser techniques. AE signals originated from microfracture of Al2O3/SUS304 plasma sprayed coatings were detected using a laser interferometer during thermal cycling. The radii of microcracks were evaluated by the inverse analysis of AE signals. Microcrack radii were also studied by the numerical analysis based on the delamination model for coating materials with various fracture toughness and an initial crack size at elevated temperature. In situ fracture toughness for microcracking was evaluated by combining the results of AE inverse analysis with those of numerical analysis. This approach revealed that the in situ toughness of the coatings is 40–50 J/m2, consistent with the results of a double cantilever beam test.

In order to suppress the microscopic mechanical damages in composite system, and thus to increase the reliability of carbon fiber reinforced plastics (CFRP), a smart composite SMA/CFRP is attracting much attention. In this application, the shape memory alloy (SMA) is expected to exert compressive stress to CFRP by reverse transformation upon heating after fabrication. However, one big problem in the fabrication process is that the curing temperature of the composite (130 °C) far exceeds the reverse transformation temperatures of Ti–Ni alloys (∼70 °C). This paper presents a new method to overcome this difficulty. The method consists of using heavily cold-worked wires to increase the reverse transformation temperatures, and of using flash electrical heating of the wires after fabrication in order to avoid damaging of the matrix around wires. By choosing the reduction of cold drawing and composition of TiNi alloys properly, it will be shown that the method is actually applicable without using special fixture jigs, which are necessary otherwise, to the fabrication of such smart composite as SMA/CFRP.

Thin foil hot press process has been developed for manufacturing metal/intermetallic compound laminate composites to induce self-propagating high-temperature synthesis (SHS) reaction between different pure metal sheets. In the present work, Nb/Nb-aluminide laminate composites were manufactured with pure Nb and Al sheets, which consist of fine Nb/Nb2Al/NbAl3 or Nb/Nb3Al/Nb2Al/NbAl3 layer structure. Microvickers hardness test and energy dispersive X-ray spectroscopy (EDS) analysis in the intermetallic compound layer demonstrate the formation of various phases, and the microvickers hardness values decrease with increasing Al/Nb atomic ratio. Although the tensile strength of laminate composites is similar to pure Nb, ductility and fracture toughness are significantly improved due to plastic deformation in Nb layer.

Welding thermal cycle and cold working are two harmful factors to ductility. In this paper, the effect of welding thermal cycle and cold working on the ductility of SN490 steel was discussed through low, medium and high-speed tensile tests, and their mechanisms of affecting ductility were revealed by microvoid model. It was found that the deterioration of ductility of SN490 by welding heat input is caused by the precipitation of a great deal of carbides, and the effect of cold working only relates to the void grow and void coalescence in SN490. Ductility decrements of SN490 steel by welding thermal cycle and cold working were also compared to each other, and the results show that welding thermal cycle is more harmful to the ductility of SN490 than cold working.

A model for the oxidation kinetics and mechanisms of Si-Ti-C-O fiber-bonded ceramics was newly developed to evaluate the oxidation behavior quantitatively at temperatures ranging between 773 and 1473K in air. The model considers the geometry changes of pores resulting from consumption by oxidation of the free carbon layer, and the oxygen consumption due to oxidation of the pore walls. A differential equation for the oxygen concentration profile along the pore was derived and solved numerically. For materials with very thin carbon layer, the geometry change of the pore has a significant effect on the oxygen concentration profile. The relative mass changes due to oxidation of (1) the external surface, (2) the carbon layer and (3) the pore walls were respectively calculated and thermogravimetric analysis (TGA) curves of the material derived from their sum. The calculated TGA curves well agreed with the experimental data. The length of carbon layer consumed by oxidation was calculated as a function of time and temperature. At low temperatures, the rates of the carbon consumption were low, but pores took place proceeded for long time. At high temperature, in contrast, the oxidation of the carbon layer was inhibited in a short time due to the quick sealing of the pore entrance by silica layer. Thus, the oxidation damage is limited only in the vicinity of the material surface.

An oxidation model for carbon interface in ceramic matrix composites was developed to evaluate the parameters that affect the oxidation rate of the carbon interface. The model considers geometrical changes of pores resulting from both consumption by oxidation of the carbon interface and oxygen consumption due to oxidation of the pore walls. The lengths of oxidized carbon interface were calculated for various cases using the oxygen concentration profile in the pore. Oxidation temperatures, interface thickness, oxygen concentration in the atmosphere, oxidation parameters on the pore walls were found to be the main parameters that control the oxidation behavior of carbon interfaces. By the present treatment, the results of interfacial shear tests could be quantitatively understood. The lengths of oxidized carbon interfaces increased with increasing temperature, interface thickness, and oxygen concentration in atmosphere. Furthermore, oxidation simulations were conducted in various ceramic matrix composites. In case of fibers and matrices with high volume expansion coefficients during oxidation reaction, the oxidation of the carbon interface was drastically inhibited.

Particle dispersed glass matrix composites have been developed in order to increase the strength of glass, and microfracture before the final fracture during bend test has been observed in many ceramics and glass composites as acoustic emission (AE) signals. Stochastic process treatment for microfracture of these composites was performed to understand the mechanical properties of these materials. Bending strength of these materials was measured as various conditions in loading rate and atomoshere. AE behavior during these tests was also detected with two transducers and a two-channel waveform acquisition system to evaluate the microfracture location in the materials. Microfracture processes during bending tests were clealy classified into four major types from the results of source location of AE, that is, (i) unstable fracture type, (ii) crack propagation type, (iii) transition type from random microfracture to crack propagation and (iv) competition type between random microfracture and crack propagation. The effect of loading rate, atmosphere and volume fraction of reinforcing particles on microfracture process was discussed.

A one directional acoustic emission (AE) source characterization has been used during a three point bending fracture toughness test on 6061 aluminum matrix composites with Al2O3 particle reinforcements of 5 and 10 μm sizes, in order to evaluate the dynamic process of micro-fracture in these materials. Different acoustic emission sources are characterized and, as a result, two types of AE events are distinguished. It is observed that at very low strain levels void nucleation is the main source for acoustic emission. At higher levels, the micro pop-in of primary voids and their eventual coalescence results in a different type of acoustic emission. In fine particle reinforced materials, when the amplitude of AE events in void nucleation at fine particles is not high enough to be detected, the main source of AE events is only the void coalescence. By increasing the particle size, the number of detectable events during void nucleation is increased.

Due to the influence of the welding thermal cycle, the toughness of structural steel generally degenerates. Recently, the intercritically reheated coarse-grained heat-affected zone (IC CG HAZ) was found to demonstrate the worst toughness in welded joint, which was associated with its fracture mechanism. In this article, two IC CG HAZs of a structural steel were prepared by welding thermal-cycle simulation techniques. For the two IC CG HAZs, the static and dynamic fracture toughness were evaluated; the fracture mechanism was also studied. Under both static and dynamic loading, cracks in the IC CG HAZ were found to initiate at the intersection of bainitic ferrite α /0 packets with different orientations, followed by propagation in cleavage. In some crack propagation regions, adjacent cleavage facets are connected by shear, thus producing dimple zones. Though the brittle fracture initiation mechanism remains unchanged, the cleavage facet size, the proportion of the dimple zones between facets, and the distance from the cracking initiation site to the crack tip vary with loading speed and welding conditions. These changes were found to be related to the variations caused by strain rate and welding conditions in fracture toughness for the IC CG HAZs.

We have evaluated the interfacial reactions of SiC fibre reinforced Al electrical power cable using low oxygen SiC fibre (Si : 62.4, C : 37.1, 0 : 0.5 mass%), and determined the relationship between the tensile strength and the amount of reaction products at the interface. The following are occurring at the SiC/Al interface: i) diffusion of Al atoms into the SiC fibre, ii) formation of needle–shape Al4C3 compounds, and iii) formation of Al9Si compounds. Formation of Al4C3 and Al9Si compounds at the interface causes the strength of SiC/Al composite electric power cable to deteriorate.

Response of a Michelson Interferometric fiber-optic sensor to impact loading was investigated. A Michelson Interferometric fiber-optic sensor was mounted on the surface of unidirectionally aligned carbon fiber-reinforced epoxy composites. Using a Charpy tester, the load was applied to the specimen at two impact energy levels. One was the case where the specimen sustained no damage; another was the case where localized damage occurred in the specimen. Both the optical interference signal and the strain were measured during the impact loadings. The spectrum analysis of the interference signal was performed by the Fast Fourier Transforms. The analytical results were compared with the predicted frequency characteristics from the strain rate. In the case where damage occurred in the specimen, the interference signal recorded before and after the peak in load and during unloading had relatively high intensity in wider frequency range than that predicted from the strain rate. This discrepancy in frequency characteristics is attributed to the vibration induced by fiber breaking or crack closure. The Michelson interferometric fiber-optic sensor proved to be effective for detecting the impact damage of the material studied.

Due to the influence of welding thermal cycle toughness of structural steel degenerates. Recently, the intercritically reheated coarse grained zone (IC CG HAZ) was found display the worst toughness in welded joint, which was associated with its fracture mechanism. In this work, two IC CG HAZs of a structural steel were prepared by welding thermal-cycle simulation techniques. For the two IC CG HAZs the dynamic fracture toughness and the fracture mechanism were studied, and the correlation between fracture toughness and fracture mechanism was also discussed. Under both static and rapidly loading, cracks in the IC CG HAZ were found to initiate at the intersection of αB0 packets with different orientations, followed by propagating in cleavage. In some places of crack propagation, adjacent cleavage facets are connected by shear, producing dimple zones. Though the brittle fracture initiation mechanism remains unchanged, the cleavage facet size and the proportion of the dimple zones between facets vary with loading speed. These changes are shown being associated with the effect of strain rate on fracture toughness. In this work, the fracture behavior of IC CG HAZ was also compared with that of base metal and prestrained steel.

The non-contact measuring system of acoustic emission (AE) by laser interferometry was developed to detect AE signals and analyze microfracture quantitatively during materials testing. The capability of this system was estimated by comparison between simulated AE signals due to glass capillary breaking and calculations using the finite element method. The system could measure AE signals during practical tensile tests of carbon fiber reinforced plastics. This technique was also applied to the thermal cycle test of ceramic/metal coatings, and AE signals during cooling were successfully detected and analyzed by a deconvolution method to evaluate quantitatively the microfracture process.

Addition of alumina particles to silicon carbide results in strongly improved toughness values. In order to come to a better understanding of this phenomenon, crack propagation is simulated for a 20 vol% alumina particles-dispersed silicon carbide composite material using the Body Force Method. Special emphasis is paid to the influence of graded compositions. Numerically obtained crack paths are compared to crack paths generated experimentally by Vickers indentations. Moreover, mechanical properties of the investigated material were measured experimentally. Microstructural toughness variations as well as the direction of crack propagation are found to be strongly influenced by residual stresses due to the mismatch between thermal expansion coefficients of alumina and silicon carbide and by the actual crack location. According to tensile residual stresses in the radial direction cracks approaching a particle are deviated circumferentially in the matrix around the particle. Moreover, the failure behavior of cracks propagating into a zone of increasing or decreasing volume fraction of alumina particles is found to behave differently as residual stress fields superimpose in the case of particle clustering. ©.

In the present work, the ductile fracture of structural steels and the effect of plastic pre-strain on ductility have been investigated by tensile test. The fracture process consisting of void nucleation, growth and coalescence was observed by scanning electron microscopy (SEM). The nucleation strain of microvoid was measured experimentally. The critical interfacial strength of particle/matrix interface was calculated by dislocation model and continuum analysis, and the void growth was evaluated by Rice-Tracey model. It was found that longitudinal void coalescence does not affect fracture even though large cracks exist, but particle position affects void nucleation. Thomason's plastic limit-load model was used to predict void growth strain. Through the analysis of ductile fracture process, the influence of plastic pre-strain on ductility was discussed.

If electrical power is transmitted by a power cable made of SiC fiber-reinforced aluminum, Al atoms diffuse into the reinforcement fiber at the transmission temperature. In this study, the diffusion coefficients of Al atoms in Hi-NicalonTM/Al system and NicalonTM/Al system were calculated. The outcomes of this study can be summarized as follows: (1) Diffusion coefficient of Al atoms in the Hi-NicalonTM SiC fiber is 10-3 times smaller than that of NicalonTM SiC fiber at transmission temperature between 300°C and 600°C. (2) Activation energy Q of Al diffusion in the two different SiC fibers are the same, but frequency factor D0 of Hi-NicalonTM SiC fiber is smaller than that of NicalonTM SiC fiber. (3) Diffusion coefficient of Al in the SiC fiber is related to the microcrystallite of the SiC fiber.

Influence of a silica layer on oxidation of free carbon in Si-Ti-C-O fiber-bonded ceramics has been investigated. The rate of oxidation of the Si-Ti-C-O fibers has been measured by thermogravimetric analysis at temperatures ranging between 773 and 1573K. The relative mass of the fibers increased parabolically and the kinetics of the oxidation followed the parabolic rate characteristic of diffusion controlled processes. The thickness of the silica layer, calculated according to a simple equation, well agreed well with the experimentally observed one. Pores created by the oxidation of free carbon were observed inside the fibers after etching the surface of a heat-treated Si-Ti-C-O fiber-bonded ceramics at 773K. Using the parabolic rate constant and the volume expansion coefficient of the fiber, the time required to close the pores by the formation of silica layer was calculated. The thickness of the free carbon layer and the oxidation rate of the fibers were the key parameters for the analysis of the oxidation behavior of the materials.

As electrical power demands increase every year, the need becomes stronger for light weight electric cables which have high transmission capacity, high thermal resistance and low sag. We have developed a SiC fiber reinforced aluminum electrical cable to meet this need. Mechanical properties of the SiC/Al composite conductor are very susceptible to iron impurity which becomes mixed in the Al matrix during manufacture of the composite conductor. In this work, we studied the effects of Fe impurity in Al on fracture behavior of the composite conductor. A preformed wire was prepared by dipping a bundle of 1500 pieces of SiC fiber (Si: 63.7, C: 35.8, O: 12.3 mass %) into molten Al in which 0.36 mass % Fe and 0.5 mass % Ti were mixed. The Ti was added to improve the wetting property. Test samples were prepared by bundling seven preformed wires together. A tensile test was carried out for the composite conductor, and pull-out behavior of SiC fiber at the fracture surface was observed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and electron probe micro analysis (EPMA). Pull-out of SiC fiber was observed at the fracture surface of the composite conductor using Fe-free Al. However, pull-out of SiC fiber was not observed at the fracture surface of the composite conductor using Fe-containing Al since Al was combined inseparably with the SiC and Fe. The fracture origin of the Fe-containing sample was a precipitated Fe-compound at the SiC/Al interface. Tensile strength of the Fe-containing sample was a half of that of the Fe-free sample. We propose the following the precipitation mechanism for the Fe compound. In manufacturing of the preformed wire, molten Al solidifies from the surface to the SiC/Al interface because of the low thermal conductivity of the SiC fiber. In the cooling process, Fe-free Ti-compound precipitates in the molten Al by a peritectic reaction. This leads to a higher concentration of Fe in the molten Al near the interface, and finally, FeAl3 compound precipitates at the SiC/Al interface.

Debonding at the fiber/matrix interface and subsequent frictional sliding considerably affect the fracture toughness of fiber-reinforced ceramic composites. In this study, the interfacial shear properties of a Si-Ti-C-O fiber-bonded composite were investigated both at room temperature and at elevated temperatures. A jig suitable for punch-out experiments was newly designed for this purpose. Punch-out experiments were performed at room temperature, 700 and 1400°C for various exposure times. It was found that the interfacial shear properties significantly depended on the oxidation behavior of the Si-Ti-C-O fiber-bonded material. At 700°C, a turbostratic carbon layer at the fiber/matrix interface is prone to oxidation, which weakens the interfacial shear properties in a catastrophic manner. At 1400°C, the quick formation of a silica layer protects the carbon from oxidation, resulting in an enhanced interfacial shear strength.

Electrical power demands are increasing every year, meaning that lightweight electric cable is needed which has high transmission capacity, high thermal resistance and low sag. Tokyo Electric Power Co., Chubu Electric Power Co. and Hitachi Cable Ltd. have been breaking new ground in the field of electric cable through the development of a SiC fiber reinforced aluminum conductor. In this work, the SiC/Al interface reaction during the manufacturing process and the electricity transmission temperature were studied by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and field emission-Auger electron spectroscopy (FE-AES) for long-term reliability assessment. No reaction products were detected at the SiC/Al interface of elemental wire consisting of 7 SiC/Al preformed wires, indicating that the wire manufacturing process was reliable. An Al4C3 product was detected locally at the SiC/Al interface of the wire which had been thermally treated in molten Al under unfavorable conditions. The activation energy, Q, of Al4C3 growth at the SiC/Al interface was about 190 kJ/mol. In the temperature range of electricity transmission, Al atoms diffused into SiC fiber during heat treatment, and the amount of the diffused Al increased with increasing treatment temperature and holding time. The activation energy of Al diffusion through the SiC/Al interface to SiC fiber was about 78 kJ/mol. Strength deterioration was not induced by Al diffusion into SiC fiber, but strength strongly depended on the formation of Al2SiO5 compound at the SiC/Al interface above 400°C transmission temperatures. Kinetics calculations indicated that the rate of strength deterioration of the composite cable, held at 300°C for 36 years, was about 5%, so that practical use of SiC/Al composite cable should not be far in the future.