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. 57 (2016), No. 2

  • The Formation and Characterization of the Primary Mg2Si Dendritic Phase in Hypereutectic Al-Mg2Si Alloys

    pp. 85-90

    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.M2015297

    The formation of a primary Mg2Si dendritic phase in hypereutectic Al-Mg2Si alloys is investigated using melt-spinning techniques. The results indicate that, at the initial stage, the primary Mg2Si crystal rapidly grows in a non-faceted manner, forming a smooth dendritic or fluted structure. As the undercooling of the process is varied, the growth behavior transitions from non-faceted to faceted. Subsequently, Mg2Si crystals grow preferentially along the [100] direction producing growth hillocks and forming stable branches. The morphology of the primary Mg2Si crystal exhibits angular facets. Furthermore, if V[100]/V[111] = √3 , the crystal grows as a perfect octahedral dendrite (the dendrite is composed of octahedrons), and if V[100]/V[111] < √3 , the crystal grows with imperfect octahedral subunits. Lastly, the growth process of the primary Mg2Si dendrites is discussed.
  • Microstructural Evolution during Partial Remelting of a 2024 Aluminum Alloy Prepared by Cold Pressing Ball-Milled Alloy Powders

    pp. 91-98

    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.M2015367

    A novel method, known as powder thixoforming is proposed. The effect of ball milling on the microstructural evolution of a 2024 alloy, prepared by cold pressing ball-milled powders is examined during partial remelting. Additionally the effect of reheating temperature on the microstructure has also been investigated. Results indicate that welding and deformation of the milled powders occurred. A semisolid microstructure with fine spheroidal primary particles results following partial remelting. Microstructural evolution comprises three stages, the rapid coarsening and formation of compact particles, separation of the welded particles with reduction of the particle size, and finally coarsening. Compared with the microstructural evolution of the powder compacts prepared by un-milled powders, the first stage is accelerated, but the second stage is retarded. The microstructural evolution is also accompanied by densification. A suitably elevated temperature is favorable to achieve a compact semisolid microstructure for thixoforming.
  • Simulation of Effect of Loading Rate on Compression Properties in the Two-Dimensional Model of Aluminum Foam Sandwich Panels

    pp. 99-102

    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.M2015359

    This article was retracted. See the Notification.
  • A Thermodynamic Modeling of the Fe–Nd–Sb System

    pp. 103-111

    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.M2015333

    The Fe–Nd–Sb system was assessed by means of the CALculation of PHAse Diagram (CALPHAD) technique. The solution phase, liquid, bcc, fcc, dhcp, and rhom, were described by the substitutional solution model. The compounds Fe17Nd2, Fe17Nd5, Nd2Sb, Nd5Sb3, Nd4Sb3, NdSb, NdSb2, Nd6Fe13Sb (τ1), Nd3Fe3Sb73), NdFeSb34), and NdFe4Sb126) were treated as stoichiometric compounds. The ternary compounds Nd2Fe5−xSb10−y2, x = 1.48, y = 5.12) and NdFe1−xSb25) were modeled as (Fe,Va)0.4667(Nd)0.1333(Sb,Va)0.4 and (Fe,Va)0.25(Nd)0.25(Sb)0.5, respectively. A set of self-consistent thermodynamic parameters of the Fe–Nd–Sb system was obtained in this study.
  • Experimental Evaluation of Specific Storage in Mudstone Considering Error Using the Flow Pump Method

    pp. 112-118

    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-M2015840

    The evaluation of hydraulic constants is generally one of the main components of reservoir engineering projects such as the development of radioactive waste disposal sites or the construction of underground CO2 storage. In the example presented here, flow pump experiments were conducted for the Horonobe mudstone to evaluate specific storage and hydraulic conductivity. The flow pump experiments were conducted with an effective confining pressure that gradually increased from 2 to 10 or 12 MPa, followed by a subsequent reduction to the initial value. The hydraulic conductivity in all cases was observed to decrease with increasing effective confining pressure in the specimens, and it did not recover to its initial value after unloading. In contrast, specific storage was observed to decrease in some specimens with increasing effective confining pressure; although this tendency was not significant in comparison to the trend observed concerning hydraulic conductivity. We therefore used theoretical analysis to calculate hydraulic constants and evaluate error ranges based on the nonlinear least-squares method. The error range value of specific storage is proposed to reduce with larger flow rates under the same confining pressures. The experimental results showed an almost linear pressure distribution from the upstream to downstream surfaces, and also showed a gradual increase in differential pressure with time in the flow pump method. Taking error ranges into account, the flow pump method is probably an easy approach for evaluating the specific storage of mudstone compared with other means of investigation that are currently available.
  • Inhomogeneous Texture Distribution in a Cu-Ag Lamellar Composite Processed by Cold Rolling

    pp. 119-126

    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.M2015349

    The inhomogeneous texture distribution in a lamellar composite incorporating two dissimilar face-center-cubic metals, i.e., Cu and Ag, under cold rolling is investigated. When the thickness reduction is higher than 80%, the heterogeneity of textures is found in the Cu layer. Namely, in the region adjacent to the rollers the Copper component dominates over the other textures, whereas in the region closed to the hetero-interface the Brass component is the dominant texture. Lattice rotations within the heterophase microstructure are then addressed by crystal plasticity finite element modeling that considers not only crystallographic (dislocation slip and twinning) but also non-crystallographic (shear banding) micromechanisms. The simulations show that the hetero-interface between the Cu and Ag layers plays an important role in texture development of the Cu layer when the two metals are co-deformed. In the Cu phase of the studied composite, significant shear banding is triggered by stress concentration at the hetero-interface compared to the positions away from the interface, which leads to the dominant Brass texture in the interface region.
  • Fatigue Properties of 6061-T6 Aluminum Alloy T-Joints Processed by Vacuum Brazing and TIG Welding

    pp. 127-134

    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.M2015343

    The increasing use of aluminum alloys in transportation including railways, shipbuilding and aeronautics demands more efficient and reliable welding processes, which requires sufficient understanding of fatigue failure. Tungsten inert gas (TIG) welding and vacuum brazing (VB) T-joints of Al–Mg–Si alloy 6061 in the artificially aged condition T6 were studied. This work focuses on the contrasting difference of fatigue behavior of T-joints made from both the traditional process of TIG welding, and the emerging process of vacuum brazing. The fatigue properties of AA 6061-T6 welding under constant amplitude (CA) and variable amplitude (VA) loading were studied. The aim of the CA part in this paper was to identify the differences between brazing and welding on fatigue performance and size effect. The fatigue experiments of TIG welding and vacuum brazing in 6061-T6 aluminum alloys were performed to investigate fatigue strengths. The test results were compared with the results suggested by the International Institute of Welding (IIW), British Standard (BS) and Eurocode 9 recommendations. Meanwhile, in terms of size effect, the thickness correction exponents were compared with the thickness correction exponents suggested by the IIW. The VA part of the work was examined to identify the effects of the mean stress which might increase fatigue lives less than predicted by linear damage summation models. The effects of the mean stress in different correction methods were evaluated.
  • Structural Characteristics and Particle Erosion Resistance of SIMA-Processed Al-Mg-Si Alloy

    pp. 135-142

    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.M2015300

    The aim of this research is to investigate the effects of the strain-induced melt activation (SIMA) process on the microstructure and particle erosion properties of 6066 Al-Mg-Si alloy. The erosion data of the SIMA-processed alloy were compared to those of the original extruded alloy (F) and a high-hardness artificially aged alloy (T6). The microstructure results show that spheroidized grains formed via the SIMA process. Globular and soft α-Al grains were surrounded by hard multi-element grain boundaries, creating a network structure. The erosion resistance of T6 was better than that of F at all impact angles due to the increase in hardness via artificial aging. The erosion resistance of the SIMA-processed alloy was higher than that of T6 at low impact angles. The SIMA process thus improves the low-angle erosion resistance of Al alloys. The hard and brittle grain boundaries of the SIMA-processed alloy protect soft grains from being destroyed by erosion particles at oblique impact. The low-angle erosion resistance decreases with spheroidized grain growth due to a decrease in the surface area of grain boundaries.
  • Solubility Measurements of Fe2O3 and Cr2O3 in Fused Na2B4O7-B2O3 in Air at 1173 K

    pp. 143-147

    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.M2015275

    The solubility of Fe2O3 and Cr2O3 powder in a binary fused Na2B4O7-B2O3 salt system was measured at 1173 K in air. The melt was continuously monitored via a basicity sensor with an oxide ion probe and a zirconia oxygen probe. The basicity of the fused salt was varied from 10.3 to 14.5 by adding B2O3 powder to Na2B4O7. For the entire range of the measured basicity, solubility of the Fe2O3 was one order of magnitude higher than that of the Cr2O3. The solubility of both the Fe2O3 and the Cr2O3 decreased with an increase in the melt basicity. From the solubility dependence on the melt basicity, both Fe2O3 and Cr2O3 are expected to dissolve via a basic dissolution reaction.
  • Weathering Steel in Industrial-Marine-Urban Environment: Field Study

    pp. 148-155

    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.M2015345

    In the present field study, we report the exposure of weathering steels in the industrial-marine-urban environment at Ennore, located near the east coast of India for 3 years. The Corrosion products viz., iron oxyhydroxides and oxides present in the rust layers were characterized using ATR-FTIR, XRD studies and quantified using TGA analysis. The specific surface area of the rust particles formed during the corrosion process were determined using N2 adsorption isotherm studies. The morphology of the corrosion products were elucidated using SEM. ATR-FTIR and XRD studies showed that the corrosion products formed on the skyward surfaces were highly more crystalline than those on the the earthward surfaces. TGA showed that the iron oxyhydroxides were major corrosion products. N2 adsorption-desorption studies confirmed the formation of compact inner rust layers with high specific surface area (SA). SEM analysis revealed that the skyward surface was smooth and compact while the earthward surface were cracked and porous. SEM images confirmed the formation of characteristic morphological structures such as sandy crystal (lepidocrocite), needle-like (goethite), cotton ball (goethite) and cigar shaped (akaganeite) structures. Further, it revealed the formation of goethite on the skyward surface as a major constituent phase in the rust layer, which was influenced by the presence of SO2 content in the environment.
    x

    Readers Who Read This Article Also Read

    1. Characterization of Nanostructure of Rusts Formed on Weathering Steel ISIJ International Vol.42(2002), No.12
  • Formation of Various Types of Globules in Co–Cu–Si–B Immiscible Alloy with Amorphous Phase

    pp. 156-162

    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-M2015835

    The formation of globules with a Co–Si–B-based amorphous core and Co–Si-based nanocrystalline shell structure embedded in the Cu crystalline matrix phase was found in rapidly solidified (Co0.75Si0.10B0.15)70Cu30 alloy. Liquid phase separation based on the Co–Cu alloy system and the high glass-forming ability of the Co–Si–B alloy system led to the formation of various types of globules in Co–Cu–Si–B immiscible alloy with an amorphous phase.
  • Effects of Mechanical Vibration Factors on Size and Shape of Solid Particles in JIS AC4CH Aluminum Alloy Semi-Solid Slurry

    pp. 163-167

    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-M2015837

    In semi-solid forming processes for metals, it is important to make slurries with fine, round solid particles. In this study, we investigated the effects of mechanical vibration on the size and shape of solid particles. The slurry was prepared by pouring molten AC4CH aluminum alloy into a vibrating stainress container, and the vibration of the container was controlled. The solid particles in the slurry became finer and rounder with increasing acceleration amplitude at the same frequency, or with decreasing frequency at the same acceleration amplitude. However, at the same velocity amplitude and different frequency and acceleration amplitude, the solid particles formed a dendritic structure at high or low frequencies. The solid particles were the finest and roundest at a frequency of 50 Hz. The calculation results for the particle diameter and the particle roundness also showed that the solid particles became finer and rounder with increasing velocity amplitude. Additionally, the shapes of solid particles were affected by the frequency and displacement amplitude. Mechanical vibration with a frequency and displacement amplitude above certain threshold values produced fine, round solid particles. Slurry containing sufficiently fine, round particles was obtained by applying mechanical vibration at 50 Hz with an acceleration amplitude higher than 49.0 m/s2.
  • Fluidity Evaluation of the AC4CH (A356) Aluminum Alloy Semi-Solid Slurry Made by Mechanical Vibration Method

    pp. 168-173

    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-M2015838

    The semi-solid process is promising as a near-net-shape method for producing high performance products. However, the method is hampered by poor formability because of low fluidity, and difficulty in making the semi-solid slurry. In previous work, we made semi-solid slurries containing small, spherical solid particles by applying mechanical vibration. In this study, we evaluated the fluidity of AC4CH aluminum alloy slurries made by applying mechanical vibration. In addition, we improved the slurry fluidity by applying shear stress to the slurry at the mold gate, and investigated the effect of the shear rate on the fluidity. The slurry was prepared by applying mechanical vibration at a frequency of 50 Hz and an acceleration amplitude of 166.6 m/s2 (17 G). The fluidity was evaluated by injecting the slurry through a gate into a metallic mold with a spiral cavity, and measuring the fluidity length. The shear rate at the gate was controlled by changing the thickness of the gate (1.0, 2.2, and 4.0 mm). The fluidity of the slurry made by mechanical vibration was 25% to 40% that of liquid aluminum. Applying shear stress at the gate increased the fluidity by approximately 30%. The α-phase particles in the specimen became finer and rounder as the shear rate increased. Therfore, semi-solid slurry with high fluidity can be obtained by applying mechanical vibration and increasing the shear rate. Moreover, the slurry prepared by mechanical vibration had similar fluidity to the electromagnetically stirred slurry prepared at high shear rates and casting pressures. Our method could be used to to fabricate complex products by the semi-solid forming process.
  • The Effect of Sub-Critical Heat Treatment on Hardness, Retained Austenite and Abrasive Wear Resistance of Hypoeutectic 16 mass% Cr-2 mass% Mo Cast Iron with Varying Vanadium Content

    pp. 174-182

    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.M2015272

    To increase the matrix hardness without complete hardening, a sub-critical heat treatment was performed by holding the as-cast iron below the pearlite transformation temperature (A1), and exposed to a hypoeutectic 16 mass% Cr-2 mass% Mo cast iron with a 0–3 mass% vanadium (V). The temperatures were held between 723 K and 923 K with 50 K intervals for 14.4–43.2 ks and then cooled via air from a fan. In the as-cast state, the hardness of the cast iron increased progressively and the volume fraction of retained austenite (Vγ) decreased gradually as the V content of specimen rose. With the sub-critical heat treatment, the hardness increased initially and then decreased with an increase in holding temperature. Conversely, the Vγ was reduced greatly when the holding temperature was elevated above 823 K. The maximum hardness in the sub-critical heat treatment (HSTmax) was obtained in the temperature range of 823–873 K, while the Vγ values were approximately 20–30%. The largest HSTmax value of 830 HV30 was obtained in the specimen with 3 mass% V. The abrasive wear resistance was evaluated by a Suga abrasion wear tester using the specimens heat-treated at selected conditions. The wear resistance increased as the V content increased with the highest wear resistance obtained in the specimens with HSTmax.
  • Effects of Fixing Carbon Nanoparticle to AZ91D Magnesium Alloy Chip Surface on Thixomold Forming

    pp. 183-187

    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.L-M2015839

    Thixomolded magnesium products have been applied as an alternative for plastic moldings in body frames for electronic equipments. AZ91D magnesium alloy chips are ordinarily used for thixomolding process. The carbon nanoparticle was fixed in the magnesium chip surface in order to improve the castability of thixomolding process. The manufacture of magnesium-carbon alloy is not easy, because carbon does not have the wettability for magnesium. However, the magnesium alloy chips fixed carbon nanoparticles make it possible to produce the magnesium-carbon alloy by thixomolding process. Since the fluidity of the magnesium alloy chip with carbon nanoparticle was improved in comparison with the AZ91D magnesium alloy chip, thin thickness molding became possible. In addition, mechanical properties of the thixomolded magnesium alloy made of the magnesium alloy chips fixed carbon nanoparticle were also improved.
  • Effect of Electromagnetic Forces on Separation of Two Immiscible Liquids in the Fe–Cu–C System

    pp. 188-192

    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.M2015364

    The recovery of rare earth elements, especially Nd and Dy, from used products is important for maintaining stable supplies. Two immiscible liquids in the Fe-Cu-C system, one that is Fe-rich and the other Cu-rich, are proposed for recycling motors that use Nd magnets. In this recovery system, mechanical separation of the Fe-rich and Cu-rich phases is important. This study aims to investigate the effect of electromagnetic forces on the separation of two immiscible liquids in Fe–Cu–C systems. The degree of mechanical separation of the Fe-rich and Cu-rich phases increases with increasing strength of the electromagnetic separation force. It was found that low magnetic field and high direct current are advantageous for the separation when the strength of the electromagnetic separation force is equal. Moreover, it was found that the electromagnetic separation force can remove the primary crystalized Fe particles from the Cu-rich liquid immediately.
  • Effects of Titanium and Boron Additions with Cooling Rates on Solidification Behavior in Aluminum Alloys for Automotive Applications

    pp. 193-200

    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.L-M2015825

    Al-Si based alloys are used to automobile parts for weight reduction. The engine block and chain cover were fabricated using the ADC12 and newly developed ADC12-M1 alloys through the high pressure die-casting. The ADC12-M1 alloy was fabricated by the addition of titanium and boron into the ADC12 alloy. Computational science such as JMatPro and Thermo-Calc was utilized in order to estimate the solidification behavior since the mechanical property of as-cast material is affected by the solidification behavior. The ADC12 and newly developed ADC12-M1 alloys belong to eutectic and hypo-eutectic alloys calculated by Thermo-Calc software, respectively. The cooling curves with the different cooling rates, fraction liquid and latent heat generation are estimated using JMatPro based on the Al-Si binary alloys in order to understand the solidification behavior between the eutectic and hypo-eutectic chemical composition. The cooling curves, fraction liquid and latent heat generation are more sensitive in the hypo-eutectic chemical composition than that in the eutectic one. The eutectic chemical composition is shifted into the higher concentration of silicon by the titanium and boron additions, resulting in that the higher difference of the yield strength is obtained in the hypo-eutectic ADC12-M1 alloy than that in the eutectic ADC12 alloy.
  • Magnetic Properties of Iron Core Compacted Powders Coated with Magnetic Insulative Film

    pp. 201-206

    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.Y-M2015836

    To improve the permeability and magnetic flux density of a powder magnetic core, we examined iron core compacted powders coated with spinel ferrite particles. Their permeability and magnetic flux density are higher than those of iron core compacted powders coated with nonmagnetic insulative film having equal resistivity: 1.4 T magnetic flux density B2k, 7.79 Mg/m3 green density, and 70 µΩ·m resistivity were achieved.
  • High-Coercivity Fe-Co Nanoparticles Prepared by Pulsed Arc Plasma Deposition

    pp. 207-211

    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.MAW201510

    Fe-Co nanoparticles were prepared on SiO2 nanoparticles by a pulsed arc plasma deposition (APD) method and the influence of discharge count during APD on the microstructure and magnetic properties of the nanoparticles was investigated. When the discharge count was 300 shots, the average particle size (d50) of Fe-Co was 3.7 nm and an unusually high coercivity (Hc) of 300 kA·m−1 was obtained. The average particle size increased and the coercivity decreased with increasing discharge count. Fe-Co nanoparticles deposited on C nanoparticles using a discharge count of 300 shots exhibited a lower coercivity than that of Fe-Co nanoparticles deposited on SiO2 nanoparticles.

Article Access Ranking

24 Jul. (Last 30 Days)

  1. Perspective toward Long-term Global Goal for Carbon Dioxide Mitigation in Steel Industry Tetsu-to-Hagané Vol.105(2019), No.6
  2. Production and Technology of Iron and Steel in Japan during 2018 ISIJ International Vol.59(2019), No.6
  3. Preface to the Special Issue “Fundamentals and Application Technologies for High-performance Hot-dip Galvanized Coatings” Tetsu-to-Hagané Vol.105(2019), No.7
  4. Insights into Accumulation Behavior of Harmful Elements in Cohesive Zone with Reference to Its Influence on Coke ISIJ International Advance Publication
  5. Microstructure and Phase of Carbon Brick and Protective Layer of a 2800 m3 Industrial Blast Furnace Hearth ISIJ International Advance Publication
  6. Understanding the Structure and Structural Effects on the Properties of Blast Furnace Slag (BFS) ISIJ International Vol.59(2019), No.7
  7. Influence of Annealing Temperature and Dew Point on Kinetics of Mn External Oxidation Tetsu-to-Hagané Vol.105(2019), No.7
  8. Effect of Si/Mn Ratio on Galvannealing Behavior of Si-added Steel Tetsu-to-Hagané Vol.105(2019), No.7
  9. Properties-to-microstructure-to-processing Inverse Analysis for Steels via Machine Learning ISIJ International Advance Publication
  10. Quantitative Analyses of Chemical Structural Change and Gas Generation Profile of Coal upon Heating toward Gaining New Insights for Coal Pyrolysis Chemistry ISIJ International Advance Publication

Search Phrase Ranking

24 Jul. (Last 30 Days)

  1. blast furnace
  2. blast furnace productivity
  3. blast furnace permeability
  4. 龍角散
  5. chinese academy of science
  6. continuous casting
  7. corrosion
  8. ladle furnace
  9. oxygen coordination number of fe ions
  10. two-phase flow mathematical model of iron and slag liquid