MATERIALS TRANSACTIONS
New Arrival Alert : OFF

You can use this feature after you logged into the site.
Please click the button below.

Log in / Sign up
ONLINE ISSN: 1347-5320
PRINT ISSN: 1345-9678

MATERIALS TRANSACTIONS Vol. 56 (2015), No. 2

  • Selected Topics on Material Strength and Thermally Activated Deformation Processes

    pp. 175-181

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014386

    Thermally activated deformation processes are discussed with reference to the studies done by the present author and his coworkers. First, dislocation motion in one- and two-dimensional periodic stress fields is analyzed to understand the deformation mechanisms of bcc metals and spinodally decomposed alloys. The role of the thermally activated kink-pair formation on the temperature and strain-rate dependence of strength is also discussed. Secondly, diffusion-controlled processes pertinent to high-temperature deformation are discussed by applying a unified and fundamental rate equation derived previously. Thirdly, mechanisms for the temperature and strain-rate dependence of polycrystals and ultrafine-grained and nanocrystalline materials are introduced. A proposed model taking into account the thermally activated dislocation depinning at grain boundaries is discussed.
  • Order Evolution in Iron-Based Alloys Viewed through Amplitude Dependent Damping Studies

    pp. 182-186

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014397

    Amplitude dependent damping and neutron thermo-diffraction studies were performed in Fe-Al-Si, Fe-Al-Cr and Fe-Si alloys. Results show that the behaviour of the strength of the amplitude dependent damping as a function of temperature is a suitable tool for determining the order changes as a function of temperature. A decrease in the order degree leads to an increase in the strength of the amplitude dependent damping, due to the dislocation mobility increases.
  • Mechanism of End Deformation after Cutting of Light Gauge Channel Steel Formed by Roll Forming

    pp. 187-192

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.P-M2014842

    Light gauge channel steel is fabricated from a steel sheet by roll forming. Cut end deformation of the channel steel was investigated by experimentation and three-dimensional finite-element simulation. During roll-forming, concave, convex, and reverse bending deformations on a flange occur and cause bending lines to diverge from the point of contact between the top roll and the flange corner. The reverse bending deformation is caused by a bending moment and a twisting moment. These moments remain on the flange. When the channel steel is cut, the release of the bending moment results in opening at both the top end and the tail end. Then, the release of the twisting moment makes the flange close at the top end and open at the tail end. Deformations at the tail end open widely with the overlap of the two moments.
  • Damping Capacities of Ti50Ni50−xCux Shape Memory Alloys Measured under Temperature, Strain, and Frequency Sweeps

    pp. 193-199

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014304

    The damping capacities of Ti50Ni50−xCux SMAs with x = 0∼20 at% were measured by DMA under temperature, strain and frequency sweep tests. The tan δ value exhibited at B2→B19 transformation is significantly higher than that at B2→B19′ transformation under temperature/strain sweep tests. In the strain sweep test, the tan δ value decreases as the frequency increases, but it increases as the applied strain increases. The tan δ curves of the strain sweep tests can be fitted by tan δ = Kεn with n values being close to the friction type model. Adding Cu enhances the tan δ values of both B19 martensite and B2→B19 transformation in 0.1∼10 Hz, but that of B19′ martensite is enhanced only at 10 Hz. From 0.1 Hz to 1 Hz, the decrement of the tan δ value in IFI term is greater than that in IFPT term for SMA with x ≥ 5 at%. In the frequency sweep test, the tan δ value increases as the x value increases under the same applied frequency, no matter whether the martensite is B19′ or B19.
  • Effects of Thickness and Crystallographic Orientation on Fatigue Life of Single-Crystalline Copper Foils

    pp. 200-205

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014352

    Thickness effect on fatigue life of pure copper single-crystal foils with two different surface orientations, (21\bar{1}) and (5\bar{11}\bar{1}), but with the same stress-axis orientation was investigated by means of S-N curve measurement and microstructural observation. Thicknesses of the foils were in range from 140 to 500 µm. Fatigue life of the (21\bar{1}) specimen was much longer (by a factor of 1000) than that of the (5\bar{11}\bar{1}) specimen within the given range of the foil thickness. The orientation dependence of fatigue life became more pronounced with decreasing the foil thickness. The size and crystal orientation dependence of the fatigue life can be explained reasonably by considering the reduction of the net area of the primary and secondary slip planes during deformation.
  • Effects of Injection Velocity on Distribution of Primary α-Phase Particles in Semi-Solid High Pressure Die Casting of JIS AC4CH Aluminum Alloy

    pp. 206-211

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.F-M2014843

    We have previously developed a new injection process with improved fluidity through applying shear stress. In this process, the product is made by injecting a solid-liquid slurry. Therefore, the microstructure of products made by this semi-solid injection process shows the dispersal of the spherical primary α-phase particles in the matrix. The primary α-phase particles and matrix are formed from the solid phase and liquid phase, respectively, when the slurry is injected. These phases have different properties, and the properties of semi-solid products are thought depend on the distribution of the primary α-phase particles. For this reason, semi-solid products have characteristic microstructures.
    In the present study, the distribution of primary α-phase particles was investigated in fluidity test specimens made of JIS AC4CH aluminum alloy, formed in a spiral cavity at various injection speeds. The number of primary α-phase particles at the edge of the specimens was higher than for other observation points. The primary α-phase particles were distributed homogeneously on the plane perpendicular to the flow direction at the edge of the specimens. In specimens formed at high injection speeds, at the observation points from the gate to the middle of the flow length, the primary α-phase particles were concentrated at the central axis of the flow direction. However, in specimens formed at low injection speeds, the primary α-phase particles were also distributed homogeneously in these areas. The concentration of the primary α-phase particles around the central axis was affected by the flow velocity in the cavity. These results suggest that the distribution of the primary α-phase can be controlled by changing the flow velocity.
  • Active-Transient Liquid Phase (A-TLP) Bonding of High Volume Fraction SiC Particle Reinforced A356 Matrix Composite

    pp. 212-217

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014295

    The microstructure and shear strength of active-transient liquid phase (A-TLP) bonded joints of high volume fraction (70 vol%) SiC particle reinforced A356 composite using an active interlayer of quaternary Al-33Cu-6Mg-1Ti (mass%) were compared with TLP bonded joints using Ti-free Al-33Cu-6Mg interlayer to establish suitable interlayer composition design route. For the developed Ti-containing active filler metal, void free dense interface between SiC particle and bond seam with C-Al-Si(-Mg) or C-Al-Si-Ti product was readily obtained, and the joint shear strength increased with increasing joining temperature from 550°C to 580°C and 600°C. While for the Ti-free interlayer, gaps between most SiC and metallic bond seam and between some matrix/bond interfaces remained, even at 600°C. The maximum shear strength of the joints using Al-33Cu-6Mg-1Ti and Al-33Cu-6Mg were 62 MPa (with small fracture unit and partial fracture path within A356 matrix) at 600°C and 31 MPa (with too large fracture unit and initial interface fracture path) at 580°C, respectively. Thus, the beneficial effects of Ti addition into interlayer on improving (i) wettability between SiC particle and metallic bond seam and (ii) joint shear strength were demonstrated.
  • Change in Mechanical Strength and Bone Contactability of Biomedical Titanium Alloy with Low Young’s Modulus Subjected to Fine Particle Bombarding Process

    pp. 218-223

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014349

    Beta-type Ti-29Nb-13Ta-4.6Zr (TNTZ), which is a recently developed biomedical titanium alloys, shows a relatively low Young’s modulus of around 60 GPa when subjected to a solution treatment.
    However, our focus in this study was on the practical applications of TNTZ in vivo because its mechanical strength decreases with solution treatment progress. Therefore, we investigated the effect of fine particle bombarding (FPB) on the mechanical properties of TNTZ subjected to a cold-swaging treatment in order to maintain its relatively low Young’s modulus and to improve its mechanical properties. The relative bone contact ratios between the cancellous bones of Japanese white rabbits and column-shaped TNTZ samples subjected to FPB were also evaluated.
    The microstructure of cold-swaged TNTZ showed a single beta-phase with a marble-like structure. Moreover, its Vickers hardness did not increase remarkably with changes in its diameter, although the average diameter of the beta-grains of solutionized TNTZ ranged from 5.0 to 20 µm, depending on the increase in the holding time of the solution treatment. The Vickers hardness and Young’s modulus of TNTZ subjected to FPB increased at the edge of the specimen surface to be around 70% and 15%, respectively, more than those of cold-swaged TNTZ. Further, the fatigue strength of TNTZ subjected to FPB became significantly higher than that of cold-swaged TNTZ in the high-cycle fatigue life region. Lastly, TNTZ with a rough surface texture (Ra: 0.65 µm) showed a relative bone contact ratio of more than 80% after undergoing FPB; this value was significantly higher than that of cold-swaged TNTZ with a very smooth surface texture (Ra: 0.07 µm).
  • Rapid Synthesis of LDHs Using Dolomite as a Magnesium Source and Application to Borate Removal

    pp. 224-228

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M-M2014844

    A rapid and efficient method based on microwave-assisted treatment has been developed for preparing layered double hydroxides (LDHs) using natural dolomite as a magnesium source. The aging temperature was 120°C and the total synthetic time was only within 6 h. The product was fully characterized by elemental composition, powdery X-ray diffraction, and scanning electron microscopy, to be highly pure hydrotalcite with a flaky shape. The synthesized adsorbent exhibited the sorption capacity of 1.34 mmol/kg which is comparable to boron-specific resin. Based on 11B MAS NMR and XRD results, the principal mechanism for borate immobilization on the LDHs is ion-exchange followed by transformation of polyborate into monoborate in a process of drying.
  • Criticality Assessment of Metals for Japan’s Resource Strategy

    pp. 229-235

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014380

    Criticality assessment of metals has been developed to analyze a country’s supply risk and vulnerability to supply restriction. This study presents Japan’s criticality of 22 metals during 2012. Whereas a past assessment focused only on minor metals, evaluation targets here included both common and minor metals. In addition, a new analytic method included mineral interest sufficiency as a criticality component. The evaluation framework developed in this study included 13 criticality components within five risk categories: supply risk, price risk, demand risk, recycling restriction, and potential risk. Weighting factors were used to aggregate components into a single score. This framework reflects a recent government announcement about Japan’s resource strategy. High criticality was found for neodymium, dysprosium, and indium due to a recent increase in demand. Niobium also had high criticality due to production concentration in Brazil. There were few differences in the aggregated criticality scores between the other minor metals and common metals. For minor metals, aggregated criticality was mainly increased by production concentration and recycling difficulty. For common metals, aggregated criticality was increased by short depletion time and growth in global mine production. Compared with a previous study, in 2012 the criticality of tungsten and tantalum were lower due to reduced domestic demand. The analytic methods and results presented in this study will be useful in developing Japan’s resource strategy.
  • Influence of Pre-Deformation of 5052H112 Alloy on Tensile Properties and Fracture Resistance under Vibration

    pp. 236-241

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014305

    This study prepared a 5052H112 alloy under different cold-rolled reductions to explore its microstructure and mechanical properties. The experimental results indicated that the cold-rolled specimens had good tensile properties and better vibration fracture resistance, due to the high densities of dislocation and small aspect ratio of crystal grain. The stress-elongation curves of all specimens showed the serrated yielding. The high densities of dislocation and small aspect ratio of crystal grain introduced by cold-rolling could hold the mobile dislocations long enough to let Mg atoms form atmospheres around them. In addition, the crack propagation behavior of all specimens showed that slip bands can be observed in the vicinity of the main crack and be suppressed by increasing the cold-rolled reduction. Crack propagation showed that rolled specimens exhibit decreasing crack propagation rates with increased matrix strengthening (cold-rolling). Therefore, it can be concluded that a large number of dislocation tangles introduced by cold-rolling are effective in improving mechanical properties.
  • Effect of Intermediate Heat Treatment on the Mechanical Properties of 3003/4343 Aluminum Clad Sheet Manufactured by Strip Casting/Clad Rolling

    pp. 242-248

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014298

    Effect of intermediate heat treatment on the microstructure evolution and mechanical properties of A3003/A4343 clad sheet manufactured through new processes were investigated. Raw materials — both A3003 and A4343 alloys — were fabricated by twin roll strip casting process, and then cold rolling and roll bonding were performed with final thickness of 215 µm. In the manufactured clad sheets, the thickness of 3003 alloy was found to be 191 µm, and that of 4343 alloy, 24 µm. Rolled and recovered microstructures appeared at low heat treatment temperatures (260°C, 280°C), and recrystallization/grain growth were noted from the A3003/A4343 interfaces at 573 K or higher temperatures, with the area (recrystallization/grain growth) gradually increasing as heat treatment temperatures increased further. According to the results of tensile tests, yield strength was 223.7 MPa, and tensile strength was 270 MPa in as-rolled state. As the intermediate heat treatment temperature increased, strengths continuously decreased, whereas elongation exhibited an increasing tendency. Until the final tensile fracture, 3003 alloy and 4343 alloy were not separated but maintained well in bonded state. Based on the results of microstructure evolution by which microstructures were divided into three areas and changed following intermediate heat treatment, the tensile properties of A3003/A4343 clad sheets were analyzed and discussed.
    x

    Readers Who Read This Article Also Read

    1. Solidification and Roll-bonding of Shells in Twin-roll Casting Process ISIJ International Vol.29(1989), No.6
    2. Bonding Quality of Copper-Nickel Fine Clad Metal Prepared by Surface Activated Bonding MATERIALS TRANSACTIONS Vol.51(2010), No.4
    3. Effect of Heat Treatment on the Bond Interface Structure of A3003/SUS304L Clad Material QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY Vol.22(2004), No.2
  • Work Softening Behavior of Zirconium-Aluminum-Nickel-Copper Bulk-Metallic-Glass by Rolling

    pp. 249-252

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014342

    Recently, “work softening behaviors” of bulk metallic glass (BMG) by shot peening was found. The purpose of this research is to investigate the work softening behavior of BMG by rolling at room temperature. The Vickers hardness of Zr55Al10Ni5Cu30 BMG decreased by first rolling, and then the hardness recovered slightly by second rolling. The density change of the BMG was measured before and after rolling. The density of the Zr55Al10Ni5Cu30 BMG increased slightly by first rolling. However, the density of the BMG decreased by second rolling. X-ray diffraction measurement was done for the BMG before and after rolling to certify the structure evolution occurred by rolling. Intensity of halo-pattern decreased slightly and a small peak appeared by rolling at room temperature.
  • Effects of Nd on the Microstructures, Mechanical Properties and in Vitro Corrosion Behavior of Cast Mg-1Mn-2Zn-xNd Alloys

    pp. 253-258

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014338

    Effects of neodymium (Nd) on the microstructures, mechanical properties, in vitro corrosion behavior, and cytotoxicity of as-cast Mg-1Mn-2Zn-xNd alloys (x = 0.5, 1.0, 1.5, mass%) have been investigated to assess whether Nd is an effective element to increase the strength and corrosion resistance of Mg alloys, and to evaluate whether those alloys are suitable for biomedical applications. The microstructures were examined by X-ray diffraction analysis and optical microscopy. The mechanical properties were determined from uniaxial tensile and compressive tests. The corrosion behavior was studied using electrochemical measurement and cytotoxicity was evaluated using osteoblast-like SaOS2 cell. The results indicate that all the cast Mg-1Mn-2Zn-xNd alloys are composed of both alpha phase of magnesium (Mg) and a compound of Mg7Zn3, and their grain sizes decrease with Nd content. Nd is not an effective element to improve the strength and corrosion resistance of cast Mg-Mn-Zn alloys. Increase of Nd content from 0.5 to 1.5 does not significantly change biocompatibility of alloys. The cast alloys exhibit much better corrosion resistance than pure Mg and good biocompatibility.
  • In Situ Synthesis of TiB/Ti6Al4V Composites Reinforced with Nano TiB through SPS

    pp. 259-263

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014347

    Titanium matrix composites reinforced with TiB whiskers were in situ synthesized by spark plasma sintering (SPS) at a temperature range of 1173–1473 K, using a mixture of 6.2 mass% TiB2, 4.1 mass% Ti, and 89.7 mass% Ti6Al4V powders. The in-situ synthesis mechanism and the effect of sintering temperature on the sintering microstructure were investigated. The results show that an increase of the sintering temperature causes the relative densities of the composites to increase and the reaction between Ti and TiB2 to be more complete. Nano-sized TiB reinforcements with a diameter of around 80 nm and fine-grained matrix with an average grain size of 12 µm are obtained after SPSed at 1373 K. Clean and perfect TiB/matrix interfaces without debonding or cracks are obtained during SPS process. Low sintering temperature and short sintering time are believed to be the main reasons for the improved fine-grained microstructure.
  • (Ti,Cr)C Synthesized In Situ by Spark Plasma Sintering of TiC/Cr3C2 Powder Mixtures

    pp. 264-268

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014327

    (Ti,Cr)C was synthesized and consolidated in situ by spark plasma sintering (SPS) of two TiC/Cr3C2 powder mixtures of distinctly different particle sizes. SPS of both mixtures successfully produced single-phase (Ti,Cr)C in two minutes at 1800°C. It was found that the nano-scale mixture consists of fine and uniformly dispersed TiC/Cr3C2 particles while the micron-scale mixture consists of particles aggregated and unevenly distributed. The (Ti,Cr)C consolidated using nano-scale mixture retained an equilibrium grain structure linear grain boundaries thanks to the fine and uniform elemental distribution. On the contrary, the grain boundaries of (Ti,Cr)C consolidated using micron-scale mixture were heavily serrated with Cr-richer composition. It is believed that Cr3C2 melts and forms networks where it starts to react with TiC to form solid solution leaving serrations along the grain boundaries because of its non-uniform distribution. The higher fracture toughness of (Ti,Cr)C consolidated from nano-scale mixture may be attributed to its uniform microstructure.
  • Damage Evaluation in Lithium Cobalt Oxide/Carbon Electrodes of Secondary Battery by Acoustic Emission Monitoring

    pp. 269-273

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014396

    Acoustic Emission (AE) technique was employed for evaluating charge/discharge damage in a lithium-ion battery. A coin-type battery of lithium cobalt oxide/carbon electrodes was used for acoustic monitoring during accelerated charge/discharge cycle test. A number of AE signals were successfully detected during charge/discharge. Microstructural observation of the electrodes after the cycle test revealed mechanical damage such as micro-cracking of the cathode and chemical damage such as solid electrolyte interphase (SEI) layer formed on the anode. The detected AE signals were classified into two distinct types (i.e., type 1 and type 2) based on the AE waveform parameters (i.e., duration and amplitude). The main frequency component of the type 1 signal with short duration and high amplitude was in the range of 121–160 kHz, whereas the frequency of type 2 signals with long duration and low amplitude was between 81 and 120 kHz. Active AE source of type 1 and type 2 signal was attributed to micro-cracking in cathode and gas bubble accompanied by SEI layer formation on anode, respectively. These results demonstrate the feasibility of the AE technique for the evaluation of charge/discharge degradation of secondary battery.
  • Formation of High Light Scattering Texture on Glass Substrates Using Spherical Silica Particles and Spin-on-Glass for Thin Film Si Solar Cells

    pp. 274-276

    Bookmark

    You can use this feature after you logged into the site.
    Please click the button below.

    Log in / Sign Up

    DOI:10.2320/matertrans.M2014362

    A high light scattering morphology on glass used as a substrate for thin film solar cells was fabricated using spherical silica particles and spin-on-glass. After deposition of Al-doped ZnO thin films, a hemispherical morphology appeared at the surface, and a high haze value of 77% (λ = 900 nm) was obtained when the cover ratio of the silica particle was 44%. The quantum efficiency of microcrystalline thin film Si solar cells was improved at wavelengths over 700 nm due to the textured morphology formed by the silica particles and spin-on-glass.

Article Access Ranking

16 Jan. (Last 30 Days)

  1. A Review of the Chemistry, Structure and Formation Conditions of Silico-Ferrite of Calcium and Aluminum (‘SFCA’) Phases ISIJ International Vol.58(2018), No.12
  2. Improving Blast Furnace Raceway Blockage Detection. Part 1: Classification of Blockage Events and Processing Framework ISIJ International Advance Publication
  3. Phase Transformation Behavior of Oxide Scale on Plain Carbon Steel Containing 0.4 wt.% Cr during Continuous Cooling ISIJ International Vol.58(2018), No.12
  4. Hydrogen Embrittlement Susceptibility Evaluation of Tempered Martensitic Steels Showing Different Fracture Surface Morphologies Tetsu-to-Hagané Vol.105(2019), No.1
  5. Improvement of Sinter Productivity by Control of Magnetite Ore Segregation in Sintering Bed ISIJ International Vol.58(2018), No.12
  6. Gasification and Migration of Phosphorus from High-phosphorus Iron Ore during Carbothermal Reduction ISIJ International Vol.58(2018), No.12
  7. Effect of TiO2 and MnO on Viscosity of Blast Furnace Slag and Thermodynamic Analysis ISIJ International Vol.58(2018), No.12
  8. Effect of Coke Size on Reducing Agent Ratio (RAR) in Blast Furnace ISIJ International Vol.58(2018), No.12
  9. High Temperature Thermal Diffusivity Measurement for FeO Scale by Electrical-Optical Hybrid Pulse-Heating Method ISIJ International Vol.58(2018), No.12
  10. Improving Blast Furnace Raceway Blockage Detection. Part 3: Visual Detection Based on Tuyere Camera Images ISIJ International Advance Publication

Search Phrase Ranking

16 Jan. (Last 30 Days)

  1. blast furnace
  2. blast furnace permeability
  3. blast furnace productivity
  4. 鉄と鋼
  5. continous annealing
  6. laser welder
  7. titanium
  8. a
  9. activity feo
  10. argon steel