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mechanical and microstructural characterization of Al7075/SiC nanocomposites fabricated by dynamic compaction

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International Journal of minerals,metallurgy and materials 2014年第3期21卷 295-303页

作者： A.Atrian G.h.majzoobi m.h.enayati h.Bakhtiari mechanical Engineering Department Bu-Ali Sina University Department of materials Engineering Isfahan University of Technology

This paper describes the synthesis of Al7075 metal matrix composites reinforced with SiC, and the characterization of their microstructure and mechanical behavior. The mechanically milled Al7075 micron-sized powder and SiC nanoparticles are dynamically compacted using a drop hammer device. This compaction is performed at different temperatures and for various volume fractions of SiC nanoparticles. The relative density is directly related to the compaction temperature rise and indirectly related to the content of SiC nanoparticle reinforcement, respectively. Furthermore, increasing the amount of SiC nanoparticles improves the strength, stiffness, and hardness of the compacted specimens. The increase in hardness and strength may be attributed to the inherent hardness of the nanoparticles, and other phenomena such as thermal mismatch and crack shielding. Nevertheless, clustering of the nanoparticles at aluminum particle boundaries make these regions become a source of concentrated stress, which reduces the load carrying capacity of the compacted nanocomposite.

关键词： nanocomposites metallic matrix composites silicon carbide nanoparticles compaction

Bulk Al–Al_3Zr composite prepared by mechanical alloying and hot extrusion for high-temperature applications

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International Journal of minerals,metallurgy and materials 2017年第8期24卷 937-942页

作者： E.Pourkhorshid m.h.enayati S.Sabooni F.Karimzadeh m.h.Paydar Department of materials Engineering Isfahan University of Technology Department of materials Science and Engineering School of Engineering Shiraz University

Bulk Al/Al_3Zr composite was prepared by a combination of mechanical alloying(mA) and hot extrusion processes. Elemental Al and Zr powders were milled for up to 10 h and heat treated at 600℃ for 1 h to form stable Al_3Zr. The prepared Al_3Zr powder was then mixed with the pure Al powder to produce an Al–Al_3Zr composite. The composite powder was finally consolidated by hot extrusion at 550℃. The mechanical properties of consolidated samples were evaluated by hardness and tension tests at room and elevated temperatures. The results show that annealing of the 10-h-milled powder at 600℃ for 1 h led to the formation of a stable Al_3Zr phase. Differential scanning calorimetry(DSC) results confirmed that the formation of Al_3Zr began with the nucleation of a metastable phase, which subsequently transformed to the stable tetragonal Al_3Zr structure. The tension yield strength of the Al-10wt%Al_3Zr composite was determined to be 103 mPa, which is approximately twice that for pure Al(53 mPa). The yield stress of the Al/Al_3Zr composite at 300℃ is just 10% lower than that at room temperature, which demonstrates the strong potential for the prepared composite to be used in high-temperature structural applications.

关键词： aluminum matrix nanocomposites mechanical alloying hot extrusion aluminides powder metallurgy

深冷轧制制备纳米6061铝合金的热稳定性评估（英文）

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Transactions of Nonferrous metals Society of China 2017年第4期27卷 754-762页

作者： m.ABBASI-BAhARANChI F.KARImZADEh m.h.enayati Department of materials Engineering Isfahan University of Technology Isfahan 84156-83111 Iran

研究深冷轧制时效态纳米6061铝合金在100~500°C下等温热处理过程的晶粒生长。透射电子显微镜观察结果表明经深冷轧制及在130°C时效30 h,合金显微组织中含有61 nm的晶粒和50~150 nm的析出相,以及0.248%的点阵畸变。此外,由于形成细小... 详细信息

研究深冷轧制时效态纳米6061铝合金在100~500°C下等温热处理过程的晶粒生长。透射电子显微镜观察结果表明经深冷轧制及在130°C时效30 h,合金显微组织中含有61 nm的晶粒和50~150 nm的析出相,以及0.248%的点阵畸变。此外,由于形成细小的强化相和纳米晶粒,合金的拉伸强度达到362 mPa。在100~500°C下进行热稳定研究,结果表明,点阵畸变得到减弱,析出相溶解,晶粒长大。X射线衍射结果表明,当退火温度高于300°C时,mg2Si相将消失。当退火温度低于200°C时,晶粒长大不明显,力学性能下降也不明显。但在300~500°C时,晶粒长大,析出相溶解和力学性能下降都比较明显。在100~200°C时,晶粒长大的活化能为203.3 k J/mol,在300~500°C时,活化能为166.34 k J/mol。讨论了析出相溶解对铝点阵常数和XRD(111)面峰位位移的影响,也讨论了PLC对应力应变曲线的影响。

关键词：力学性能表征 X射线衍射铝合金体变形晶粒生长晶粒细化

非晶态Ni_(55)Nb_(35)Si_(10)合金的非等温纳米结晶动力学（英文）

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Transactions of Nonferrous metals Society of China 2019年第2期29卷 358-364页

作者： h.mINOUEI G.h.AKBARI m.h.enayati S.I.hONG Department of metallurgy and materials Science Shahid Bahonar University Department of material Engineering Nanotechnology and Advanced Material InstituteIsfahan University of Technology (IUT) Department of Nanomaterials Engineering Chungnam National University

采用差示扫描量热法(DSC)研究机械合金化制备的Ni_(55)Nb_(35)Si_(10)非晶合金的非等温结晶动力学。结果表明,该非晶合金在加热过程中表现出单级结晶,导致非晶态基体中形成金属间化合物纳米晶体。由基辛格方程确定的合金结晶表观活化能... 详细信息

采用差示扫描量热法(DSC)研究机械合金化制备的Ni_(55)Nb_(35)Si_(10)非晶合金的非等温结晶动力学。结果表明,该非晶合金在加热过程中表现出单级结晶,导致非晶态基体中形成金属间化合物纳米晶体。由基辛格方程确定的合金结晶表观活化能较高(468 k J/mol),说明该非晶合金具有较高的热稳定性。采用等转换法对结晶过程中活化能的变化进行研究,活化能从结晶开始一直缓慢降低至结晶分数α=0.35,然后几乎保持不变直至结晶结束。通过测定Avrami指数,解释非晶合金非等温结晶的纳米结晶机理。透射电镜研究表明,在退火过程中通过纳米结晶可对非晶态合金进行微观结构调控。成核速率随时间的延长而减小,结晶机理主要受三维扩散控制生长支配。在Sestak-Berggren自催化模型的基础上,得到定量描述非等温结晶动力学的预测方程。

关键词：非晶合金动力学纳米结晶 DSC 活化能

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.m.FEIZABAD m.h.YAS Department of mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQm)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQm)

Crystal structure and luminescence dynamics of highly pure Lim(PO_(3))_(3):Eu^(3+)(m=Sr,Ca) red phosphors for white light emitting diodes

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Journal of Rare Earths 2024年第8期42卷 1470-1478,I0002页

作者： Payal Khajuria m.manhas A.K.Bedyal Ankush Vij h.C.Swart Vinay Kumar Department of Physics and Astronomical Sciences Central University of JammuRahy-Suchani.Samba1143J&KIndia Department of Physics School of SciencesCluster University of JammuCanal RoadJammu180001India Department of Physics University of Petroleum and Energy StudiesDehradunUttarakhand248007India Department of Physics University of the Free StatePO.Box 339BloemfonteinZA 9300South Africa

highly pure red phosphors Lim(PO_(3))_(3):Eu^(3+)(m=Sr,Ca) doped with Eu^(3+)(1 mol%) were synthesized via solution combustion method and their crystal structure and luminescence dynamics were studied to explore its suitability in white light emitting *** Rietveld refinement analysis of the powder Xray diffraction patterns reveals that the phosphors belong to the pure triclinic phase of LiSr(PO_(3))_(3) and LiCa(PO_(3)) with space group P-1(2).The scanning electron microscopy images showed the agglomerated *** photoluminescence emission spectra under 393 nm show an orange band at 594 nm and a red band at 613 nm ascribed to ^(5)D_(0)→^(7)F_(1).^(5)D_(0)→^(7)F_(2) transitions of Eu^(3+)ion in both the ***,the spectroscopic properties such as luminescence behaviour,and Stark splitting were used to examine the symmetry of Eu^(3+)ions in Lim(PO_(3))_(3):Es^(3+)(m=Sr,Ca) phosphors in terms of distortion induced upon *** Stark splitting shows that the actual site symmetry for Eu^(3+)ion was estimated to be D_(2) type for both *** photometric properties of LiCa(PO_(3))_(3):Eu^(3+)such as Commission International de l'Eclairage coordinates(x=0.64,y=0.36) near to the standard one(red),high color purity(95%) and higher brightness reveal that the phosphor has the capability of acting as a red component in n-UV white light emitting diodes.

关键词： Photoluminescence Phosphate WLEDs Stark splitting Rare earths

Influence of erbium on structural,and charged particles,photons,and neutrons shielding properties of Ba_(1-x)Er_(x)SnO_(3) perovskite ceramics

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Journal of Rare Earths 2024年第4期42卷 724-732页

作者： m.K.h.hamad Nidal Dwaikat m.h.A.mhareb m.I.Sayyed R.m.hamad Y.S.m.Alajerami m.A.Almessiere Gameel Saleh Ahmad hussein Alomari K.A.Ziq Department of Basic Sciences School of Social and Basics SciencesAl Hussein Technical UniversityKing Abdullah II St 242Amman11831Jordan Department of Physics College of Engineering and PhysicsInterdisciplinary Research Center for Advanced MaterialsKing Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Department of Physics College of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Basic and Applied Scientific Research Center Imam Abdulrahman Bin Faisal UniversityP0.Box 1982Dammam31441Saudi Arabia Department of Physics Faculty of ScienceIsra UniversityAmman11622Jordan Department of Nuclear medicine Research Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityPo.Box 1982Dammam31441Saudi Arabia medical Imaging Department Applied Medical Sciences FacultyAl Azhar University-Gaza CityPo.Box 1277Palestine Department of Biophysics Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityPo.Box1982Dammam 31441Saudi Arabia Department of Biomedical Engineering College of EngineeringImam Abdulrahman Bin Faisal UniversityPo.Box 1982Dammam31441Saudi Energy&minerals Regulatory Commission Amman11821Jordan

Five perovskite ceramics samples of Ba_(1-x)Er_(x)SnO_(3) with x=0.00,0.05,0.10,0.15,and 0.20 were synthesized using the conventional solid-state reaction *** prepared samples were characterized by X-ray diffraction(XRD),Fourier transforms infrared(FTIR),and UV-Vis *** shielding properties against ionizing radiation were also *** XRD analysis shows the perovskite cubic structure as the major phase in all *** FTIR reveals a distinctive band around 614-620 cm^(-1) ascribed to the antisymmetric O-Sn-O ***-Vis spectroscopy was used to determine the bandgap according to diffuse reflectance,and the results display a fixed enhancement in the bandgap from 3.2 to 3.3 eV for all ***-ray shielding properties of the synthesized samples were experimentally measured and compared with XCOm computational *** relative differences(Δ,%)between experimental and theo retical values are low and fall within the 0.446%-7.10%*** addition of Er leads to the enhanced density,neutron,and gamma shielding *** contrast,charged particles’shielding parameters gradually reduce with rising Er *** results suggest that Ba_(1-x)Er_(x)SnO_(3) samples can be used in different radiation shielding applications.

关键词： Perovskite Ceramics Gamma ray shielding mass stopping power Rare earths

The multi-impurity system in CdSe nanoplatelets:electronic structure and thermodynamic properties

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Communications in Theoretical Physics 2024年第3期76卷 165-173页

作者： D A Baghdasaryan V A harutynyan E m Kazaryan h A Sarkisyan Russian-Armenian University H Emin 1230051YerevanArmenia Institute of Applied Problems of Physics 25 Nersisyan St0014YerevanArmenia

This paper theoretically studies the impurity states and the effects of impurity concentration and configuration on the optical,electrical,and statistical properties of CdSe nanoplatelets(NPLs).An image charge-based model of electron-impurity interaction is *** charge-carrier energy spectra and corresponding wave functions depending on the impurity number and configuration are *** electron binding energies are calculated for different NPL *** is shown that the image charge-based interaction potential that arises due to the dielectric constants mismatch is much stronger than the interaction potential that does not take such a mismatch into ***,it is demonstrated that the binding energies are increasing with the number of *** calculate the canonical partition function using the energy levels of the electron,which in turn is used to obtain the mean energy,heat capacity,and entropy of the non-interacting electron *** thermodynamic properties of the non-interacting electron gas that depend on the geometric parameters of the NPL,impurity number,configuration,and temperature are studied.

关键词： nanoplateletes thermodynamic properties impurity states

Effect of cold-working on corrosion induced damage in lug joints

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Defence Technology（防务技术） 2024年第6期36卷 175-182页

作者： Ramanath m.N Chikmath L. murthy h. Department of Aerospace Engineering Indian Institute of Technology-MadrasChennai 600036India Department of Aeronautical Engineering KLS Gogte Institute of TechnologyBelagavi 590008India

Lug joints are preferred joineries for transferring heavy loads to parent components in aerospace *** experience corrosion due to environmental conditions,improper surface finishes and rubbing displacement between the pin and *** causes damage of different sizes and shapes near the *** degradation due to corrosion-induced damage is modelled as a through-pit at one of the identified critical locations through stress *** effect of this pit on fatigue crack initiation life is ***-hole is pre-stressed by cold-working and the benefits of inducing plastic wake on the intended performance of the lug joint during the damages due to corrosion are brought out and compared with non-cold-worked *** analysis is performed on this lug joint with *** results obtained highlight the benefits of cold-working and the methodology can be extended to damage growth and analyse the effect of surface treatments for better structural integrity of components of aerospace vehicles.

关键词： Lug joint Corrosion Crack initiation Cold-working Structural integrity