The work-hardening phenomenon is one of the most well-known and utilized mechanical properties of crystalline materials. This paper overviews the history of the study of work-hardening of face-centered cubic (FCC) single crystals under monotonic and uniaxial loading and presents some of our work since the 1980s. Chapters 1 and 2 of this paper review the history of work-hardening research beginning in the 19th century, and emphasize that the concept of dislocation was first presented by a Japanese researcher, Keiji Yamaguchi in 1929, prior to the work of Taylor, Orowan, and Polanyi. Progress of research in the mid-20th century, backed up by the invention of the transmission electron microscope is then briefly introduced. Chapter 3 discusses the most important question in the mechanism of work-hardening, namely, what is the dislocation microstructure that causes work-hardening? The role of deformation bands, i.e., kink bands and bands of secondary slip is accentuated from experimental approach. Chapter 4 describes the modeling and numerical approach to the work-hardening. Tensile deformation of numerical models for single crystals with initial inhomogeneities show subtle activity of secondary slip superimposed on the primary one and the formation of deformation bands. The important role of the mean free path of dislocations is emphasized. Finally, directions for future research on work-hardening behavior in face-centered cubic metals are outlined.

This Paper was Originally Published in Japanese in J. Japan Inst. Met. Mater. 88 (2024) 91–105. The Abstract was slightly changed.

Structural metallic materials used in hydrogen gas or corrosive environments may suffer from loss of ductility owing to hydrogen atoms (hydrogen embrittlement). To design hydrogen-resistant metallic materials, it is crucial to elucidate the mechanism of hydrogen entry and diffusion. However, visualization of corrosion-induced hydrogen entry and microstructure-dependent hydrogen diffusion requires a highly sensitive hydrogen detection technique with high spatial and temporal resolutions. Hydrogen visualization techniques using polyaniline (PANI), which is a hydrogenochromic sensor, have recently been developed. The PANI layer reacts with atomic state hydrogen in a metal, changing its color from blue to yellow. Thus, the hydrogen distribution in the metal can be analyzed by observing the color distribution of the PANI layer using a digital camera. Owing to the high sensitivity and spatial resolution of hydrogenochromic sensors, corrosion-induced hydrogen entry and microstructure-dependent hydrogen diffusion have been successfully visualized in real time. In this paper, the principles of the sensor and representative application examples are introduced.

Structure searches using first-principles calculations were performed for the NO₂ adsorption on the TiO₂ anatase surfaces. The stable and metastable structures were enumerated for uni- and bimolecular adsorptions on the (101) and (001) anatase surfaces. In this study, exhaustive structure searches were performed using tDIRECT, which is based on the global optimization algorithm, DIRECT. This is in contrast to the structure searches based on chemical intuition in the literature, which exclusively targeted the unimolecular adsorptions. The number of enumerated structures was much larger in the bimolecular adsorption systems than in the unimolecular adsorption ones, indicating the importance of an exhaustive, rather than empirical, structure search for multiple adsorption systems. The adsorption energy of the obtained stable structure was −0.38 and −1.06 eV in the unimolecular adsorption, and −1.46 and −3.26 eV in the bimolecular adsorption on the (101) and (001) surfaces, respectively. Vibrational analyses showed that the eigenfrequencies and/or the IR-activity of the vibrational modes in the adsorption structures depended on the surface structures and the number of adsorbates.

In this study, we developed a method for reproducibly fabricating high-performance nano-grained bulk Si-Ge thermoelectric materials free from severe oxidization. In our previous work, the oxidization of Si-Ge during mechanical alloying and sintering processes had led to poor reproducibility of the value of electrical resistivity. We found that co-sintering with Ti, which is more easily oxidized than Si and Ge near the sintering temperature, effectively reduces the oxygen concentration in the nano-grained bulk Si-Ge samples. The oxygen concentration in the sample co-sintered with Ti was found to be less than 2.4 at%, and electrical resistivity was found to be less than 3.9 mΩ cm at 922 K with good reproducibility. High Seebeck coefficient (more than 400 µV K⁻¹) and low thermal conductivity (less than 1 Wm⁻¹K⁻¹) were simultaneously achieved by constructive electronic structure modification via iron doping and nano-crystallization, respectively. As a consequence, we succeeded in obtaining a surprisingly large value of dimensionless figure of merit, ZT = 4 at 922 K, and the temperature range of ZT exceeding 1 extended at high temperatures above 700 K.

This Paper was Originally Published in Japanese in J. Thermoelec. Soc. Jpn. 21 (2025) 141–146.

Employing the first-principles approach grounded in density functional theory, the interfacial properties of the Al (111)/HfB₂ (0001) were investigated to provide a basis for understanding the reinforcement mechanism in HfB₂ ceramic nanoparticle-strengthened aluminum alloys. Our comprehensive investigation demonstrates that among six structurally distinct Al (111)/HfB₂ (0001) interfaces, the B-terminated H stacking (H-B) interface characterized by the aluminum atoms occupying positions above the second-layer atoms of the HfB₂ substrate exhibits superior interfacial stability, as evidenced by its maximal work of adhesion (4.74 J/m²) and minimal interfacial energy (−0.54 J/m²). The disparity in charge density and partial density of states further elucidate that H-B interface display pronounced covalent bonding characteristics, while the Hf-terminated H stacked (H-Hf) interface is dominated by metallic interactions. The exceptional stability of the H-B interface promotes coherent epitaxial growth of α-Al on the HfB₂ substrate, while simultaneously inducing grain refinement in primary α-Al phases, thereby mechanical properties of metal matrix.

AA2618 aluminum alloy is well-known as an age-hardenable aluminum alloy with higher strength at elevated temperatures. In this study, the effect of dynamic precipitation on creep properties of AA2618 forged aluminum alloy was investigated by creep test, tensile test, transmission electron microscopy and differential scanning calorimetry. The differently aged three samples with varied yield stress: i.e. short-, middle- and long-aged samples, were prepared and then crept at 180°C under applied stress of 160–250 MPa. Although yield stress of short-aged sample was the lowest at room temperature and 180°C, the creep rupture time was the longest, and the minimum creep rate was the lowest among the three samples. Such a discrepancy between tensile and creep strength was attributed to dynamic precipitation in short-aged sample, in which newly formed precipitates during creep test compensate the softening induced by the growth and coarsening of existing GPB zones and S′/S phases. Therefore, it was clarified from this study that less stable precipitate microstructure with higher solute concentrations in the α-Al matrix of short-aged sample is good for creep resistance of this alloy system, although the tensile strength is lower than those of middle- and long-aged samples.

Mg-9Al-1Zn (AZ91Mg) alloy was multi-directionally forged at room temperature (rMDFed) employing by small pass strains of Δε = 0.1 up to a cumulative strain of ΣΔε = 2.0 at maximum. Ultrafine-grained structure with an average grain size of 0.2 µm was obtained via subdivision mainly by multiple mechanical twinning. The dense mechanical twinning as well as small pass strains suppressed sharp basal texture evolution, which enabled rMDFing up to high cumulative strain regions, and hence evolution of homogeneous ultrafine-grained structure. Well-balanced mechanical properties of very high yield strength of 520 MPa, ultimate tensile strength of 550 MPa, hardness of 1.32 GPa with reasonable plastic strain to fracture of 5% were achieved. These superior mechanical properties were results of extremely high forging stress over 400 MPa with changing forging direction to induce multiple slips and multiple twinning, which brought extremely large strain hardening and grain orientation randomization.

In this study, based on the understanding of the effect of Sc content on the microstructure of Al-1.2Mg-0.8Si alloy, the T6 heat treatment process was adopted to simultaneously improve the strength and plasticity indexes of this alloy. Microstructural characterization of precipitated phase morphology, grain refinement, etc., and testing of mechanical properties such as strength and elongation, the key role of the Sc element in the strengthening mechanism and plasticity regulation of the alloy is revealed. The experimental results show that, under the condition of metal-type casting, with the increase of Sc content from 0 to 0.7 mass%, the primary Al₃Sc phase as the heterogeneous nucleation core increases and significantly refines the grains from the initial coarse grains to uniform equiaxial crystals, and the grain refinement is as high as 92.9% compared with the initial state. The corresponding mechanical properties show a significant increase in tensile strength from 113.3 MPa to 216 MPa. It is noteworthy that the T6 heat-treated alloys with 0.4 mass% Sc additions show excellent overall performance, with a 63% increase in tensile strength compared to the alloys without Sc additions, and elongation after fracture maintained at a high level of 18.7%. This finding provides new theoretical support for overcoming the strength-plasticity inversion dilemma in conventional Al-Mg-Si alloys and indicates the direction of process optimization.

Soft actuators are gaining attention as flexible components for soft robotics. Responsive materials that respond to external stimuli such as light are often used as the driving part of the soft actuator. For example, thermo-responsive soft actuators are fabricated by bilayer polymer films of different thermal expansion coefficients. Heating of such bilayer polymer films by plasmon heating enables the soft actuators to be driven remotely by light. In the present study, we report the fabrication of plasmonic heating driven responsive soft actuators by using metal-organic framework (MOF) thin films as supports of plasmonic nanoparticles. The thin films of Cu₂(bpydc)₂ (bpydc = 2,2′-bipyridine-5,5′-dicarboxylate) of which metal ion adsorption capacity is high were fabricated on Cu₂(bpdc)₂ (bpdc = 4,4′-biphenyldicarboxylate) which grown on ceramics precursor, Cu(OH)₂. The actuating was operated by plasmon heating of Ag nanoparticles contained in MOF thin films inserted in between the two polymers, PDMS (poly(dimethylsiloxane)) and PVDC (poly(vinylidene chloride)). Two polymers have different thermal expansion coefficient so that they work as soft actuators by plasmon heating. Such fabrication process of soft actuators would pave the way for development of advanced devices in the field of soft robotics.

This Paper was Originally Published in Japanese in J. Jpn. Soc. Powder Powder Metallurgy 71 (2024) 112–117.

The strength, deformation, and hydraulic properties of geomaterials, which constitute embankments, vary with fine fraction content. Therefore, numerous research studies have been conducted regarding the effects of fine fraction content on the engineering properties of geomaterials. However, there have only been a few studies in which the effects of fine fraction content on the soil skeletal structure have been quantitatively evaluated and related to compaction and mechanical properties. In this study, mechanical tests were conducted on geomaterials with various fine fraction contents to evaluate their compaction and mechanical properties focusing on the soil skeletal structure and void distribution. Furthermore, an internal structural analysis of specimens using X-ray computed tomography (CT) images was conducted to interpret the results of mechanical tests. As a result, it was discovered that the uniaxial compressive strength increased with fine fraction content, and the maximum uniaxial compressive strength was observed at a low water content, not at the optimum water content. Additionally, the obtained CT images revealed that large voids, which could serve as weak points for maintaining strength, decreased in volume, and small voids were evenly distributed within the specimens, resulting in a more stable soil skeletal structure.

Internal friction in magnesium alloys with a varying volume fraction of the long-period stacking-ordered (LPSO) phase was investigated using polycrystalline Mg-Zn-Y alloys with the aim of elucidating the initial dislocation dynamics. The phase composition and microstructure were characterised via electron microscopy and X-ray diffraction. Results show that Young’s modulus and the temperature-dependent modulus softening scale nearly proportionally with LPSO content, highlighting its strong influence on both elastic and damping properties. The most pronounced softening occurs the single-phase fully LPSO alloys, likely due to their intrinsic characteristics and impact on mobile dislocation density. Internal friction measurements reveal that amplitude-independent damping increases with LPSO content, while the critical strain amplitude for amplitude-dependent damping decreases. Notably, the critical stress for dislocation motion is significantly lower than the characteristic CRSS for basal slip, emphasising the crucial role of thermal activation in dislocation liberation at very low applied cyclic stresses/strains.

This study examines the influence of various surface finishing methods on the vacuum brazing of SUS304 stainless steel using BNi-2 filler metal. It explores the relationship between surface roughness, microstructural characteristics, and brazing tensile strength to optimize joint performance. The results demonstrate a clear correlation between surface roughness and brazed joint strength, emphasizing the critical role of surface preparation in the brazing process. Among the tested methods, mechanical grinding polishing showed the most significant improvement, achieving a tensile strength of 546 MPa, equivalent to 89% of the base metal’s strength. Microstructural analysis revealed that controlled surface roughness enhances filler metal flow and suppresses the formation of brittle phases in the brazing layer. These findings highlight the importance of selecting appropriate surface finishing techniques to improve joint quality, productivity, and durability. Furthermore, the study shows that high joint strength can be achieved without additional fine polishing, offering a cost-effective and time-efficient approach for industrial applications.

The √area parameter model is widely used for predicting the fatigue limit of materials containing small defects based on the assumption that a small defect can be regarded as a crack. Although the model was successfully applied to various materials, its applicability to high-strength steel requires further validation. In this study, the fatigue limit was evaluated using specimens of vacuum-quenched and tempered martensitic steel in which a drill hole, an electric discharge machined (EDM) notch, and a pre-crack were introduced. The fatigue limit of the specimen with the pre-crack was consistent with the prediction of the √area parameter model, whereas the specimens with the drilled hole and EDM notch exhibited higher fatigue limits, indicating that these defects could not be regarded as cracks in the fatigue limit evaluation. Fracture surface observations confirmed that the fatigue limits were determined by the crack non-propagation limit rather than the crack initiation limit. Furthermore, finite element analysis indicated that differences in defect-induced stress fields influenced the fatigue crack propagation, leading to deviations in the fatigue limits. These findings contribute to an accurate estimation of the fatigue limit of high-strength steels.

Hull steels undergo significant cold deformation and annealing during ship construction processes. However, current non-destructive evaluation techniques lack the capability for on-site assessment of mechanical property variations post-fabrication. This study systematically investigates the effects of plastic deformation and recrystallization annealing on 10CrNi3MoV hull steel through controlled variations in deformation rate and annealing temperature. The mechanical property evolution was quantitatively characterized through both conventional tensile testing and instrumented indentation testing (IIT). Experimental results demonstrate that IIT effectively captures the mechanical property changes induced by plastic deformation and subsequent annealing, thereby enabling non-destructive evaluation of tensile properties in high-strength low-alloy steels. Furthermore, a model was established to characterize the relationship between yield strength and plastic deformation rate, as well as the true stress-strain behavior based on post-deformation tensile properties. This model enables rapid prediction of yield strength and accurate description of the stress-strain relationship after plastic deformation.

Based on electronic structure calculations and the strategic selection of commonly available transition metal elements, this study proposes Co-Ni-Al shape memory alloys (SMAs) with transformation temperatures exceeding 373 K, guided by two electronic parameters derived from fundamental electronic concepts. Nine Co-Ni-Al alloys with γ+β dual-phase structures were synthesized via cold crucible levitation melting: Co-40Ni-18Al, Co-23Ni-18Al, Co-6Ni-18Al, Co-40Ni-23Al, Co-23Ni-23Al, Co-6Ni-23Al, Co-40Ni-28Al, Co-23Ni-28Al and Co-6Ni-28Al. They showed γ+β dual phase and volume fraction of each phase could be evaluated by two electronic parameters bond order and d-orbital. Alloys exhibiting both high shape recovery rates and high phase transformation temperatures were concentrated within specific regions of the Bo–Md diagram. Furthermore, manganese (Mn) was selected as a fourth element taking into consideration the effect on the enhancement of the mechanical properties and phase transition temperature. The Co-29Ni-27Al-3Mn alloy emerged as a promising quaternary alloy, demonstrating excellent shape memory behavior characterized by high recovery strain and transformation temperatures. The promising alloy showed an excellent shape memory behavior. This provides a theoretical basis for composition optimization and enhancement of shape memory properties in Co-Ni-Al alloys.

The reduction reaction and slag-metal separation behavior are important factors influencing metal recovery rates during copper slag cleaning. In this study, theoretical calculations combined with experiments were carried out to investigate the effects of temperature, reductant dosage and CaO on the recovery of Cu and Fe, while revealing the separation behavior of metal particles from slag. Theoretically, the Fe₃O₄ reduction is cascaded and prioritized over Fe₂SiO₄ reduction. Increase of temperature and reductant dosage effectively promotes the recycling of Cu and Fe, and the appropriate amount of CaO promotes the depolymerization of complex silicate structure of slag and the aggregation of metal particles. The temperature was increased from 1623 K to 1698 K, the recoveries of Cu and Fe were increased from 88.46% and 73.68% to 96.78% and 95.88%, respectively. During initial stage of copper slag cleaning, Fe₃O₄ is reduced, and metal particles aggregate and settle in the middle and lower layers. Subsequently, Fe₂SiO₄ is reduced to metallic Fe, which combines with matte to form alloy and settle to bottom slag. The optimal recovery rates for Cu and Fe are 96.78% and 95.88%, respectively. The results of this study provide a reliable reference for strengthening the slag-metal separation, recovering Cu-Fe binary liquid alloy and improving the utilization rate of copper slag in the copper slag cleaning.

The corrosion behavior of the inner surface of commercially available pineapple cans (unlacquered tinplate cans) were investigated using accelerated pack test and electrochemical measurements. In the accelerated pack test, the tin concentration in the contents increased over time. The increase was greater as the tin-iron alloy layer became exposed, and the internal pressure also increased. Electrochemical measurements showed that the corrosion potentials of tin, iron, and the tin-iron alloy layer were increasingly noble, in that order, supporting the corrosion behavior of tin in the accelerated pack test. Based on these results, it is suggested that corrosion of the inner surface of the can is represented by five stages.

This Paper was Originally Published in Japanese in Zairyo-to-Kankyo 74 (2025) 94–99.

We studied the suppression of pitting corrosion in copper tubes used for heat transfer in cooling water systems with absorption chillers. The corrosion was caused by the relation between the carbon film on the copper tube surface and the water quality flowing through the tube. Phosphonic acid and benzotriazole (BTA) were used as water treatment chemicals to suppress pitting corrosion. Silicate and calcium ions are effective for corrosion resistance of copper in the presence of phosphonic acid and BTA. In addition, we also studied the effects of chloride ions, known to have a corrosive effect, on copper pitting corrosion. In this study, hydrogen carbonate ions were added to these factors including phosphonic acid, BTA, silicate ions, calcium ions, and chloride ions, and the effects of hydrogen carbonate ions on copper pitting corrosion were investigated. As the hydrogen carbonate ion concentration increased, the number of sites of pitting corrosion decreased, and the potential decreased in the immersion test. Anode polarization curve measurements showed a tendency toward a parallel shift toward the cathode side. These results suggested that increasing hydrogen carbonate ion concentration resulted in greater inhibition of corrosion.

This Paper was Originally Published in Japanese in J. Japan Inst. Copper 63 (2024) 149–152.

Electromagnetic crimping is a crimping method for applying uniform crimping force to metal parts in a shorter forming time than conventional press crimping. It is difficult to measure and determine the crimping force acting on metal parts because the crimping force affected by the magnetic field and Lorentz force induced by current in a forming coil is invisible. Additionally, current is affected by the circuit characteristics of an electromagnetic forming instrument and the shape of a forming coil. Hence, it is difficult to design a forming coil. In this study, simulation procedures were developed for designing a forming coil. First, the circuit characteristics of an electromagnetic forming instrument were identified to predict current in a forming coil accurately. Second, electromagnetic crimping was simulated by the coupled analysis of a circuit simulation to consider the effects of circuit characteristics and the finite element method to consider shape of a forming coil. Finally, a forming coil for electromagnetic crimping was designed by using the developed simulation procedures. Required current in the designed coil was determined. The shape of the crimped workpiece in the simulation was similar to an experimentally crimped sample. These results indicate that the developed simulation procedures are useful for designing the shape of a forming coil.

This Paper was Originally Published in Japanese as J. JSTP 64 (2023) 93–100.

Iron-powder pack (IPP) treatment, which has been proposed as a novel surface modification technique, was applied to a hard chromium film plated on low-carbon steel to further enhance its hardness. As the first step, a piece of pure chromium was used to examine the effectiveness of IPP treatment, since chromium is known to be covered with a stable oxide film. It was embedded in mixtures of iron, graphite and alumina powders and subsequently heat-treated at 1273 K for 3.6 ks in a nitrogen flow. The volume ratio of iron to graphite was varied from 0:5 to 4:1, and that of iron + graphite to alumina was fixed at 5:3. When mixtures with the iron powder was used, the diffusion of carbon and nitrogen into pure chromium occurred. The specimen heat-treated using a 3:2:3 mixture of iron, graphite and alumina powders showed an average surface hardness of HV = 1940 because of the formation of reaction products like M₇C₃ (M = Fe, Cr). However, the microstructure near the chromium surface was inhomogeneous. This would be caused by contact and a reaction with an iron powder used in mixtures. To avoid such a situation during heating, low-carbon steel coated with a hard chromium film was wrapped with a weighing paper and then was subjected to the above IPP treatment. There was no influence of the paper on the diffusion of carbon and nitrogen, and a relatively homogeneous microstructure was obtained. In addition, the hardness of the modified film was more than HV = 1500 and was about two times higher than that of as-plated state, which had a hardness of approximately 710.

Horizontal direct chill (HDC) casting technology has become a research hotspot in the field of aluminum alloy forming due to its continuous production characteristics, high safety and low cost advantages. As a key process parameter, casting speed significantly affects the solidification microstructure evolution and defect formation mechanism of ingot by adjusting the solidification thermodynamic conditions. In this study, the effects of casting speed (170 mm/min–250 mm/min) on the solidification behavior and microstructure properties of horizontally continuously cast 6082 aluminum alloy were systematically explored by combining numerical simulation and experimental verification. Based on the Ansys platform, a thermal-flow coupling model was constructed, and the temperature field distribution, cavity morphology evolution, billet shell thickness and liquid phase rate variation characteristics under different casting speeds were analyzed. Multiple control experiments were carried out to reveal the relationship between casting speed and microstructure, secondary phase distribution and mechanical properties. The results show that under the condition of low speed (180 mm/min), the thickness of the billet shell increases to 11.5 mm due to the slow advancement of the solidification interface, but the long melt residence time causes the cold insulation defect in the upper area (width 2.01 mm), and the proportion of coarse β-Al(Fe,Mn)Si phase at the bottom reaches 1.8%, which seriously affects the mechanical properties. When the velocity is increased to 210 mm/min, the melt shrinkage capacity and solidification rate form a dynamic equilibrium, the ingot presents a uniform equiaxed crystal structure (average grain size 108.9–117.8 µm), the second phase dispersion distribution (volume fraction 1.0%–1.1%), and the tensile strength is stable in the range of 248.3 MPa–267.2 MPa. When the speed is further increased to 240 mm/min, the intensification of coagulation shrinkage leads to a significant solute retention effect, and the coarsening of the bottom β-Fe phase (accounting for 1.8%), which induces a significant performance gradient of 48.1 MPa between the strength of the heart and the bottom.

Understanding rock resistivity is essential for interpreting subsurface resistivity structures obtained from electromagnetic surveys. We can estimate porosity or water content from resistivity using rock physics models; however, predicted results are strongly dependent on the model with the assumption of an internal pore microstructure. In this study, we evaluated the relationship between the resistivity and pore microstructure of clay-free sandstones based on digital rock physics while focusing on tortuosity. Simulation results demonstrated an increase in resistivity and its anisotropy with decreasing porosity. Tortuosity values calculated from local electric current further explain the evolution of resistivity, which suggests that smaller pore volumes (i.e., porosity) prevent pore connectivity and enhance tortuosity, resulting in higher resistivity and anisotropy. The resistivity of high-porosity data can be fitted using Archie’s equation with empirical parameters, whereas the resistivity of low-porosity data cannot. This illustrates the difficulty in applying Archie’s equation to low-porosity rocks; however, the equivalent channel model reproduced the resistivity over a wide porosity range using the calculated tortuosity. Our results confirm that tortuosity is a key factor for determining electrical properties.

This Paper was Originally Published in Japanese in J. Soc. Mater. Sci., Japan 73 (2024) 232–239. The abstract and all figures are slightly modified.

The present study examines the influence of sputtering power from 80 W to 110 W on the structural, morphological, optical, electrical, and thermoelectric characteristics of Indium-doped ZnO thin films that are produced on glass substrates via radio frequency-magnetron reactive sputtering. The In-doped ZnO thin films show a highly oriented hexagonal wurtzite structure with preferential development along the (002) plane after being doped with 2 at% In. The surface morphology of In-doped ZnO thin films becomes rougher with increased sputtering power, which correlates with improved crystallinity. UV-Vis spectroscopy demonstrates a high average transmittance (>80%) within the visible spectrum and a variable optical band gap ranging from 3.38 to 3.44 eV. Hall measurements indicate increased carrier concentrations (>10²¹ cm⁻³), enhanced electron mobility (up to 6.22 cm²/V·s), and minimal resistance (∼10⁻⁴ Ω·cm). The Seebeck coefficient of In-doped ZnO thin films increases with sputtering power, achieving 48.04 µV/K, while the power factor maximizes at 261.07 µW·m⁻¹·K⁻². These findings highlight the potential of In-doped ZnO thin films for application in transparent electronics and thermoelectric devices.

The ten best papers for young scientists were awarded by The Japan Institute of Light Metals (JILM) and The Japan Institute of Metals and Materials (JIMM) in Materials Transactions. Here, the awarded papers are briefly summarized as current trends in research of Materials Transactions. Among the ten best papers, six were from JILM for young scientists whose ages are 30 or below and four from JIMM for those with ages of 35 or below. A total of six best papers were originally published in Japanese in Journal of the Japan Institute of Light Metals and Journal of The Japan Institute of Metals and Materials as cutting-edge research in JILM and JIMM. In association with all the awarded papers, special issues edited in Materials Transactions are also briefly introduced to show the recent activities of Materials Transactions.