MATERIALS TRANSACTIONS
Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Volume 55 , Issue 12
Showing 1-22 articles out of 22 articles from the selected issue
  • Takayuki Shinkawa, Kenji Matsuda, Yoshimitsu Hishinuma, Katsuhiko Nish ...
    2014 Volume 55 Issue 12 Pages 1781-1785
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: November 14, 2014
    JOURNALS FREE ACCESS
    The Er2O3 layer fabricated by MOCVD method on SUS316 substrates before and after hydrogen permeation test were investigated to know their surface morphology and structure by SEM and TEM. The surface morphology of this layer was granular structure with size of about 0.3–0.6 µm in diameter. According to the cross sectional TEM (X-TEM) observation, the Er2O3 layer with 1–1.3 µm thickness was formed on SUS316 substrate by MOCVD method in this research and no remarkable defects or cracks were detected. The Er2O3 layer had the columnar structure and their mean width was 0.3–0.5 µm, and it is also in good agreement with mean width of a single column measured by TEM observation. The growth direction of Er2O3 column was ⟨110⟩Er2O3, which is the same with as each sample before and after hydrogen permeation test, it strongly suggested that the Er2O3 is a better candidate material for insulating coating of a liquid lithium blanket.
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  • Jun-ichi Imai, Osamu Taguchi, Gyanendra Prasad Tiwari, Yoshiaki Iijima
    2014 Volume 55 Issue 12 Pages 1786-1791
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: November 08, 2014
    JOURNALS FREE ACCESS
    Diffusion coefficients of carbon in niobium and molybdenum have been determined by the residual activity method with radioactive tracer 14C in the temperature ranges between 1168 and 1567 K for niobium and between 1271 and 1669 K for molybdenum. The temperature dependences of the diffusion coefficient of carbon in niobium and molybdenum are expressed by D/m2 s−1 = 2.2 × 10−6 exp(−152 kJ mol−1/RT) and D/m2 s−1 = 5.2 × 10−6 exp(−163 kJ mol−1/RT), respectively. Since the solubility of carbon in molybdenum is very small, the diffusion of carbon in molybdenum is strongly influenced by carbide precipitation at lower temperatures.
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  • Ryoichi Furushima, Kiyotaka Katou, Setsuo Nakao, Zheng Ming Sun, Koji ...
    2014 Volume 55 Issue 12 Pages 1792-1799
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: October 31, 2014
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    The effect of oxygen content in WC-FeAl powder is examined on mechanical properties of the sintered composites. The oxygen content is varied by controlling the milling and/or drying processes of the WC-FeAl mixed powder. The WC-FeAl composites are obtained by sintering the mixed powders with the pulse current sintering technique. Transverse rupture strength is improved by reducing the oxygen content in the mixed powder whereas the difference of microstructure and composition is not observed clearly. Some results suggest that oxidation of FeAl during the preparation of the WC-FeAl mixed powder affects the mechanical properties of WC-FeAl products. It is concluded that oxygen content is very important for controlling the mechanical properties of WC-FeAl products.
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  • Shu Ning Wen, Jiann Shieh
    2014 Volume 55 Issue 12 Pages 1800-1805
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: October 18, 2014
    JOURNALS FREE ACCESS
    Metal nanoparticles with nanoscale spacing are promising materials for the detection of single molecules through surface-enhanced Raman scattering. To increase the sensitivity of nanoparticles through the use of a nanoscale substrate, we fabricated various Ag NP–decorated silicon nanowalls for the Raman spectroscopic detection of rhodamine 6G (R6G). The sensitivity of detection was affected by the nanowall depth and was influenced by several parameters: the AgNO3 concentration for metal-assisted etching, the HF/H2O2 etching time for nanowall formation, and the Ag evaporation time for nanoparticle growth. For an approximately 400-nm-deep nanowall substrate having the optimal surface filling ratio and etching depth, we obtained an ultrahigh enhancement factor of 1.1 × 109 for the detection of R6G at a concentration of 10−11 M.
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  • Hong-En Chen, Shejuan Xie, Zhenmao Chen, Toshiyuki Takagi, Tetsuya Uch ...
    2014 Volume 55 Issue 12 Pages 1806-1815
    Published: December 01, 2014
    Released: November 25, 2014
    JOURNALS FREE ACCESS
    Plastic deformation may occur in a mechanical structure during its manufacturing and service process, and may cause serious problem in the structural integrity. Therefore, a reliable pre-service or in service quantitative non-destructive evaluation (NDE) of plastic deformation is very important especially for a structure after suffering giant load such as a large earthquake. However, there is still no satisfactory method being established for the quantitative NDE of plastic deformation in key structures such as those of a nuclear power plant. For this purpose, three electromagnetic NDE methods, i.e., Magnetic Barkhausen Noise (MBN), Magnetic Incremental Permeability (MIP) and Magnetic Flux Leakage (MFL) method are studied via experiments in this paper to investigate their feasibility for evaluation of plastic deformation in carbon steel SS400. A special testing system integrated these three electromagnetic NDE methods is established to measure the magnetic property of test-pieces with different plastic deformation, which was introduced by a tensile testing machine. It is found that the measurement signals of all these three methods have clear correlation with the plastic strains and show coincident tendency, which reveals the validity of these methods for the quantitative evaluation of plastic deformation. Among these methods, the MFL signals are of higher stability and repeatability but of relative low spatial resolution. The MBN method can give better resolution but of bigger standard deviation and is also not valid to evaluate a plastic strain of large scale. On the other hand, the MIP signals are more sensitive to the liftoff of sensor and to the remanent magnetization status, i.e. of more noise. Therefore, to measure the feature parameters of these three methods at the same time with an integrated testing system and to evaluate the plastic strain through signal fusion may give a better detectability and evaluation precision.
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  • Haihong Li, Xueqin Sun, Shangzhou Zhang
    2014 Volume 55 Issue 12 Pages 1816-1819
    Published: December 01, 2014
    Released: November 25, 2014
    JOURNALS FREE ACCESS
    The mixing enthalpy (ΔH), the excess entropy (SABE), the excess Gibbs free-energy (GABE) and the component activities (a) of Cu-Ce binary alloy system were calculated based on Miedema’s model and some general thermodynamic relations. Results showed that the values of ΔH, SABE, and GABE of Cu-Ce binary alloy in 1555 K were all negative in the whole range concentration. The activities of Cu and Ce had negative deviation from Raoult’s Law, which indicated that there was a strong interaction between Cu and Ce. The calculation results of the mixing enthalpies and the activities of Cu and Ce agreed well with the experimental results. Cu6Ce phase precipitation behavior in thermodynamics and dynamics were also discussed. Furthermore, combining the experiment, the existence of Cu6Ce phase particles was observed using scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS).
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  • Sadatoshi Koroyasu
    2014 Volume 55 Issue 12 Pages 1820-1826
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: November 08, 2014
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    The effects of the casting design and reduced pressure in a flask on the mold filling of a molten aluminum alloy in the expendable pattern casting (EPC) process were investigated experimentally. An aluminum alloy plate was cast using the EPC process, and the arrival times of the molten metal were measured for three coats with different permeabilities. The use of a high permeability coat, or the condition of applying reduced pressure, led to a higher melt velocity. The melt velocity did not increase in proportion to the coat permeability. The experimental values for the arrival time of molten metal were compared with the calculated values based on the mold filling model used in the previous study. The values were in relatively good agreement except for when the coat permeability was very low. The arrival time in top pouring was almost the same as that in bottom pouring, except for when the coat permeability was very low. The melt velocity in the top pouring did not drop, even when the coat permeability was low.
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  • Nurul Nadiah Mahmud, Sanjay Kumar Vajpai, Kei Ameyama
    2014 Volume 55 Issue 12 Pages 1827-1833
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: October 24, 2014
    JOURNALS FREE ACCESS
    Lightweight ultra-fine grained (<1 µm size) YSZ-SiC composites, with a combination of high hardness, high flexural strength and high fracture toughness, were successfully prepared by mechanical milling followed by spark plasma sintering. The YSZ-SiC composites exhibited high hardness (13–20 GPa), which is very similar to the hardness of SiC. The YSZ-SiC composites also exhibited high flexural strength (as high as 1142 MPa) and high fracture toughness (up to approximately 8 MPa-m1/2), which are similar to those of the fine-grained YSZ. Such a combination of mechanical properties was attributed to the fine microstructure with a distinct feature consisting of almost continuous network of YSZ phase around SiC particles. It has been demonstrated that a combination of these unique microstructural characteristics was very effective in suppressing the initiation of cracks and governing the path of their subsequent growth during fracture, leading to excellent combination of mechanical properties.
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  • Tatsuro Katsumura, Takaaki Iguchi, Hideto Kimura, Jun Yanagimoto
    2014 Volume 55 Issue 12 Pages 1834-1840
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: November 14, 2014
    JOURNALS FREE ACCESS
    Although the closure of defects at the center of billets on rolling such billets is an important subject, a method of quantity evaluation for such closure has not yet been clarified. Therefore, to establish a method for such quantity evaluation, we study such defects using experiments and finite element analysis including asymmetric rolling, especially with respect to the integration of the hydrostatic stress Gm. The results showed that stress was widely distributed, as determined in the experiment and in the FEM analysis of rolling at the edge around an artificial central hole in which defects were simulated. Therefore, it was suggested that, to evaluate the behavior of defect closure, the size of defects and the shape of the grooved roll used should be taken into account.
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  • Changsheng Zhu, Jinfang Jia, Hong Zhang, Rongzhen Xiao, Li Feng
    2014 Volume 55 Issue 12 Pages 1841-1846
    Published: December 01, 2014
    Released: November 25, 2014
    JOURNALS FREE ACCESS
    A Sola-phase field model combined Sola algorithm with phase-field model is established. It is difficult to implement real-time simulation as the computational grids increase. Taking pure SCN for example, the solidification microstructure evolution process in the presence of flow has been accelerated on a GPU with CUDA programming. The GPU implementation of the Sola-phase field model is introduced in this paper. The acceleration results of the dendritic growth simulation under flow by using a single NVIDIA GeForece GTX780 GPU with different memories are also evaluated. The results show that the GPU computation with the shared memory achieves the best acceleration effect, which is 56.16 times faster than that on a single CPU core for 2048 × 2048 grid size. In addition, the simulation results on GPU tally well with that on CPU, which indicates the reliability of GPU-accelerated phase-field simulation.
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  • Anmin Yin, Quan Yang, Fei He, Xiaochen Wang, Christ Glorieux
    2014 Volume 55 Issue 12 Pages 1847-1851
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: October 18, 2014
    JOURNALS FREE ACCESS
    The paper presents a rapid texture measurement method and r-value prediction model for cold-rolled sheets using XRD nondestructive testing data. First the textural through-thickness inhomogeneity in two deep drawing steels, DC05 and DC06, was measured by XRD and described using the orientation distribution function (ODF), the results reveal that the textural inhomogeneity of cold-rolled sheet exhibits little through-thickness inhomogeneity. Then the experimentally measured r-values were compared with theoretical r-values calculated using the reaction stress model applied through the sheet thickness direction, a good match was found between r-values predicted by the reaction stress model based on the rapid texture measurement method at the sheet surface and experimental data. Finally the prospect for industrial application of this technique was discussed in detail.
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  • Akira Takeuchi, Akihiro Makino
    2014 Volume 55 Issue 12 Pages 1852-1858
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: October 18, 2014
    JOURNALS FREE ACCESS
    The crystallization processes of Fe83.3+xB7−xP9Cu0.7 (x = 0 to 2.5 at%) amorphous alloys were thermodynamically assessed using Thermo-Calc software with TCFE7 database for Fe-based alloys. The analysis of the alloys for a primary crystallization precipitating bcc-Fe revealed metastability among four phases comprising bcc-Fe, two kinds of Fe-based amorphous phases that are rich in Fe-B and Fe-P and crystalline Cu-rich phase. The roles of P and Cu additions to the Fe-based amorphous alloys are thermodynamically interpreted as stabilizing the remaining amorphous phase at the primary crystallization. The dual Fe-rich amorphous phases due to the inclusion of P characterize a heterogeneous amorphous structure of NANOMET family alloys comprising Fe and metalloids mainly and without early-transition metals.
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  • Isao Matsui, Yorinobu Takigawa, Daisaku Yokoe, Takeharu Kato, Tokuteru ...
    2014 Volume 55 Issue 12 Pages 1859-1866
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: October 24, 2014
    JOURNALS FREE ACCESS
    A strategy for producing highly ductile electrodeposited bulk nanocrystalline metals with face-centered cubic structures was developed in a Ni–W alloy model system. Bulk nanocrystalline Ni–W alloys with similar grain size (20–30 nm), and varying crystallographic orientations were produced. The electrodeposited alloys showed tensile elongation ranging between 0 and 13%. Scanning ion microscopy reveled that all electrodeposited alloys had similar meso-scale structures that are typical of electrodeposited metals. This indicated the variation of ductility and fracture surfaces was not caused by cluster structures filled with nano-grains. The tensile behavior of the bulk nanocrystalline Ni–W alloys could be explained by considering the effects of growth processes during electrodeposition on the presence of hydrogen and defects. Our discussion surrounding Ni–W alloys outlines the conditions necessary to obtain the high tensile ductility. Our findings are in good agreement with those for other electrodeposited nanocrystalline face-centered cubic metals. We also provide guidelines for selecting electrodeposition conditions to produce bulk nanocrystalline metals with face-centered cubic structures and high tensile ductility.
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  • María Luz Carrera Jota, Margarita García Hernánde ...
    2014 Volume 55 Issue 12 Pages 1867-1871
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: November 08, 2014
    JOURNALS FREE ACCESS
    In the present work, the effect of SiO2 was analyzed in different molar ratios (Lu : Si = 4 : 1, 6 : 1, 8 : 1, 10 : 1 and 1 : 0), in order to prepare SiO2 embedded Lu2O3:Eu3+ sol-gel luminescent powders, from a modified PVP-containing solution. The crystalized SiO2 embedded Lu2O3:Eu3+ powders were characterized by Fourier transform infrared spectroscopy revealing the presence of high intensity bands associated with siloxanes groups at 700°C, which could indicate a cross-linked Si-O groups to Lu2O3:Eu3+. X-ray diffraction results showed that cubic phase was present in the powder heat treated at 500°C and remained up to 700°C. The powders SiO2 embedded Lu2O3:Eu3+ powders in molar ratio Lu:Si 4 : 1 and 10 : 1 masked the crystallinity of glass ceramic. The SiO2 effect on the morphology of the glass ceramic systems was monitored by scanning electron microscopy observations, from these results homogenous particles were obtained for Lu:Si 6 : 1 and 8 : 1 systems. Photoluminescence studies showed that adding silica to the ceramic systems increases the typical emission to around λem = 611 nm.
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  • Soon-Hyeok Jeon, Do Haeng Hur, Hye-Jin Kim, Yong-Soo Park
    2014 Volume 55 Issue 12 Pages 1872-1877
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: October 18, 2014
    JOURNALS FREE ACCESS
    To determine the influence of oxygen content on the formation of inclusion in 27Cr-7Ni hyper duplex stainless steel, samples were analyzed by scanning electron microscopy. Electrochemical tests were also conducted, which revealed that an increase in oxygen content reduces the resistance to pitting corrosion of the alloys. This was attributed to the formation of numerous inclusions, as well as an increase in the area of micro-crevices that occur between the inclusion and metallic matrix, and which act as initiation sites for corrosion pits.
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  • Takatoshi Kakimoto, Junya Goto, Shinpei Fujii, Keiichi Koyama, Shoji I ...
    2014 Volume 55 Issue 12 Pages 1878-1884
    Published: December 01, 2014
    Released: November 25, 2014
    JOURNALS FREE ACCESS
    The electronic and magnetic properties of Mn2Sb1−xAsx (where x = 0,0.5,1) are investigated from first-principles total-energy calculations. The predicted magnetic ground states (ferrimagnetism for x = 0 and antiferromagnetism for x = 1) are in agreement with experimental observations; however, this is not the case for x = 0.5. Here, it is found that the artificial change of the surrounding atoms of Mn stabilizes the antiferromagnetism. A similar change stabilizes ferrimagnetism (antiferromagnetism) for x = 1 (x = 0). These results indicate that the environment around the Mn atoms plays a very important role in the stabilization of antiferromagnetism in the Mn2Sb1−xAsx system. In addition, an analysis of the sign of an effective exchange interaction as a function of the distance between the Mn atoms is performed.
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  • Sookyung Kim, Jae-chun Lee, Kwang-sek Lee, Kyoungkeun Yoo, Richard Dia ...
    2014 Volume 55 Issue 12 Pages 1885-1889
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: November 08, 2014
    JOURNALS FREE ACCESS
    The waste lead (Pb)-free solder leaching process in hydrochloric acid (HCl) solution with hydrogen peroxide (H2O2) followed by separation of copper (Cu) and tin (Sn) was investigated to separate tin, silver (Ag), and copper as an individual component from waste Pb-free solder. The dissolution of Sn increased with increasing temperature and HCl concentration. The concentrations of Sn and Cu increased to 27090 g·m−3 and 191 g·m−3, respectively, under the leaching condition with 1 kmol·m−3 HCl, 0.8 kmol·m−3 H2O2 at 50°C and 400 rpm for 120 min, while Ag is not detected in all leaching tests. The Sn and Cu components are thus successfully separated from Ag by hydrochloric acid leaching with hydrogen peroxide. To precipitate selectively Cu ions from the leach solution, the method to add Sn powder has been investigated. Thus, 92.8 g·m−3 (1.46 mol·m−3) of Cu could be removed successfully from the leach solution with Sn under the following conditions; 30°C in temperature; 400 rpm in agitation speed; 0.3 ml min−1 in N2 flow rate; 0.1 g Sn powder addition to 100 cm3 leach solution.
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  • Kotaro Doi, Sayaka Miyabe, Shinji Fujimoto
    2014 Volume 55 Issue 12 Pages 1890-1894
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: November 08, 2014
    JOURNALS FREE ACCESS
    Dissolution and repassivation of type 316L stainless steel during cyclic deformation were examined in a simulated body environment. Samples were exposed to simulated body fluid (SBF) with or without cells, and then subjected to cyclical deformation in the SBF kept at cell culturing condition. The cyclic stress ratio and maximum stress were 0.1 and 300 MPa, respectively. Transients of stress, strain and corrosion potential were recorded during the test.
    The corrosion potential became less noble immediately after the start of the test, but started to increase again after about 10∼1000 cycles. The minimum corrosion potential depends on the treatment prior to the deformation: the lowest value was observed for the specimen previously immersed in SBF for 1 day without cells, whereas the highest one was shown by the specimen immersed for 1 week in the presence of cultured cells. This reveals that proteins and cells inhibit metal dissolution during deformation. On the other hand, the time needed for the potential revert to noble was the longest for the sample containing cells, and shortest for the cell-free sample immersed for 1 day. This denotes that proteins and cells also suppress repassivation.
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  • Junhyun Choi, Yosep Han, Donghyun Kim, Soyeon Park, Jayhyun Park, Jaik ...
    2014 Volume 55 Issue 12 Pages 1895-1899
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: November 08, 2014
    JOURNALS FREE ACCESS
    Mesoporous silica was prepared from anorthite-clay via mechanical activation (i.e., grinding) and selective acid leaching method. The pore characteristics of the mesoporous silica with different grinding time and acid treatment time were systematically characterized and compared with those prepared via heat treatment followed by acid treatment. Particle size, X-ray diffraction (XRD), BET surface area, thermal gravity (TG), and solubility analyses were carried out to characterize the samples. The XRD results showed that grinding and heat treatment dramatically altered the crystal structure of the samples, resulting in the change in weight loss curves of the corresponding samples from TG analysis. The results for pore size distribution of the prepared samples revealed that acid-treatment led to significant changes in the pore structure of the samples while grinding and heat-treatment without acid-treatment showed negligible influence on the pore structure. More specifically, acid-treatment increased the specific surface area of the ground and heat-treated samples regardless of acid-treatment. Furthermore, solubility tests for anorthite-clay samples showed that there is a positive relationship between the solubility of anorthite-clay and the specific surface area of mesoporous silica, indicating that the increase in the specific surface area of mesoporous silica was attributed to the increase in the solubility of anorthite-clay.
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  • Jianchao Ma, Lingling Wang, Yanli Wu, Xianshu Dong, Qingliang Ma, Chen ...
    2014 Volume 55 Issue 12 Pages 1900-1902
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: October 24, 2014
    JOURNALS FREE ACCESS
    A facile method was developed for the synthesis of Fe3O4 nanoparticles with a higher specific surface area. Na2CO3 and hydrazine were added during the co-precipitation of ferrous and ferric species, without the assistance of any organic reagents or templates. The results show that the prepared Fe3O4 nanoparticles had a specific surface area of 286.9 m2/g, with satisfactory size and purity, thus exhibiting superparamagnetic properties with a relatively strong saturation magnetization (91 emu/g) at room temperature. This method is inexpensive, nontoxic, and reproducible.
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  • Joong-Hwan Jun
    2014 Volume 55 Issue 12 Pages 1903-1905
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: November 14, 2014
    JOURNALS FREE ACCESS
    This study aimed to investigate the damping capacities of Mg–(0–9)%Sn casting alloys. An increase in the Sn content led to an increase in the Sn-rich area and the volume fraction of Mg2Sn phase, and to a decrease in the damping levels both in the strain-amplitude-independent and strain-amplitude-dependent regions. The evaluation of the microstructural evolution indicates that the higher Sn solute concentration in the α-Mg matrix and the increased number density of Mg2Sn precipitates are responsible for the deterioration of the damping capacities in the strain-amplitude-independent and strain-amplitude-dependent regions, respectively.
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  • J. A. Liu, F. Gao, Y. Q. Rao, C. L. Wu, Y. Liu
    2014 Volume 55 Issue 12 Pages 1906-1908
    Published: December 01, 2014
    Released: November 25, 2014
    [Advance publication] Released: October 24, 2014
    JOURNALS FREE ACCESS
    Spheroidal calcium chloride particle was applied as space holder to produce the aluminum foams via replication casting route. The pore shapes of the aluminum foams are similar to the shapes of spheroidal calcium chloride. The compressive properties of the aluminum foams with spheroidal cell were studied. A good reproducibility in compressive property is achieved at a similar relative density due to the homogenous macro pore-structure of the aluminum foams. The compressive strength and the energy absorption capacity of the aluminum foams increase with increasing relative density. The relation between compressive strength and relative density of the foams is in accord with the Gibson-Ashby model.
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