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The characterization of Fe-rich phases in a high-pressure die cast hypoeutectic aluminum-silicon alloy

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Journal of Materials science & Technology 2020年第16期47卷 54-62页

作者： X.y.Jiao c.F.Liu Z.P.Guo G.D.Tong s.L.Ma y.Bi y.F.Zhang s.M.Xiong school of Materials science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Tsinghua UniversityBeijing 100084China china FAW Foundary co. LTDChangchun 130011China

Both microstructural characteristics and fracture behavior of Fe-rich phases in a high-pressure die-cast hypoeutectic Al-si alloy were *** was focused on the morphology and formation mechanism of Fe-rich phases,together with their influence on *** show that primary Ferich phases exhibited in blocky shape precipitated from liquid while secondary Fe-rich phase in a large net shape was distributed along eutectic boundary participating in a ternary eutectic *** synchrotron X-ray tomography characterization,three Fe-rich phases with different morphologies,i.e.,polyhedral shape,fine compact shape and chinese script-type shape were extracted along the radial *** slow-shot speed promoted the polyhedral Fe-rich phase to precipitate in slow-shot sleeve while decreased the formation of fine compact and chinese script-type Fe-rich phases in die *** of a worse deformation compatibility,polyhedral Fe-rich phases fractured and became stress concentration sources before the failure of the casting.

关键词： Hypoeutectic Al-10si Fe-rich phases Fracture morphology High pressure die casting

Bifurcation of rupture path by nonlinear damping force

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Applied Mathematics and Mechanics(English Edition) 2011年第3期32卷 285-292页

作者： A. A. ZAINAL c. c. D. LING s. y. FAIsAL Department Mathematics Faculty ScienceUniversiti Teknologi MalaysiaSkudai 81310JohorMalaysia

The linear damping mechanism of the Rayleigh waves is extended to the nonlinear one. conferring to the model, the analytical method is chosen for the solutions. These solutions depict the unusual bifurcation of the ru... 详细信息

关键词： bifurcation of rupture path antisoliton soliton

Enhanced pitting corrosion resistance of a Zr-based metallic glass by ultraviolet light irradiation

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Journal of Iron and steel Research International 2023年第8期30卷 1642-1649页

作者： Z.chen D.P.Wang s.Wang y.X.Geng y.X.Guo y.c.Wu Z.G.Liu y.y.Zhang y.X.Wang school of Materials science and Engineering Jiangsu University of Science and Technology.Zhenjiang 212003JiangsuChina school of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003JiangsuChina

The influence of ultraviolet light irradiation on the pitting corrosion performance of a Zr_(2)Ni metallic glass was examined using electrochemical methods and immersion test in 0.05 mol/L Nacl *** the results of potentiostatic polarization,the pitting potential of the ultraviolet light-irradiated sample shifted positively with a value of~300 mV,revealing the enhanced pitting corrosion resistance of the *** corrosion morphology after the immersion test also demonstrated lower degree of corrosion damage and improved pitting resistance of the sample with ultraviolet light irradiation.X-ray photoelectron spectroscopy analysis revealed more zirconium enrichment in the passive film and no chloride ions adsorption for the samples with ultraviolet irradiation,accounting for the suppression of the pit generation and *** findings indicate that ultraviolet light irradiation improves the pitting corrosion resistance of the Zr-based metallic glasses,which are promising structural materials to be used in corrosion environments with high ultraviolet irradiation.

关键词： Metallic glass Pitting-corrosion Ultraviolet light irradiation Passive film

Nanocomposites with auxetic nanotubes

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International Journal of smart and Nano Materials 2010年第2期1卷 83-94页

作者： F.scarpa s.Adhikari c.y.Wang AccIs University of BristolBristolUK school of Engineering Swansea UniversitySwanseaUK

The effect of extreme and negative Poisson’s ratio(auxetic)behavior from non-reconstructed defective(NRD)carbon nanotubes on the mechanical properties of nanocomposites is *** carbon nanotubes(cNTs)produced by electronic or ion irradiation are metastable structures,which however can exist at low temperatures or when surrounded by an external medium(*** nanoropes of matrix in a composite).The defective nanotubes were modeled using an equivalent atomistic-continuum formulation for the mechanical properties of the c-c bond that provides both the effective mechanical properties of the atomic link and the thickness of the bond *** defective cNTs are modeled as truss-type finite elements,with the defective atoms selected using a random Latin hypercube *** mechanical properties(young’s modulus,shear and bulk modulus,as well as Poisson’s ratios)are obtained using uniaxial tensile loading *** defective nanotubes not only exhibit negative Poisson’s ratio(PR),but also extreme positive PR values based on the percentage of defective atoms,radius and aspect ratio of the ***-shritkman bounds are used to calculate the effective properties of nanocomposites with different matrix combinations and cNT *** on the properties of the defective cNTs,extreme values of bulk and shear modulus for the nanocomposites are recorded.

关键词： carbon nanotube auxetic behavior defect nanocomposite

synthesis,spectroscopic characterization and thermal studies of some lanthanide(Ⅲ) nitrate complexes with a hydrazo derivative of 4-aminoantipyrine

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Journal of Rare Earths 2009年第5期27卷 705-710页

作者： K.Mohanan c.J.Athira y.sindhu M.s.sujamol Department of chemistry University of Kerala

A heterocyclic ligand synthesized by the coupling of diazotized 4-aminoantipyrine with acetylacetone reacted with lanthanide(Ⅲ) nitrate to form complexes of the type [Ln(HAAP)2(NOз)з] where, Ln=La(Ⅲ), ce(Ⅲ), Pr(Ⅲ), Nd(Ⅲ), sm(Ⅲ), or Gd(Ⅲ) and HAAP=3-{[2-(N-1-phenyl-2,3-dimethylpyrazol-3-in-5-on-4-yl)]hydrazone}pent-2,3,4-trione. The ligand and metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, UV-Visible, infrared, far infrared and proton NMR spectral data. The spectral data revealed that the ligand existed in the hydrazo form and coordinated to the metal ion without deprotonation in a neutral tridentate manner, through carbonyl oxygen of pyrazolone ring, hydrazo nitrogen and carbonyl oxygen of the acetylace-tone moiety. The molar conductance values adequately supported their non-electrolytic nature. The ligand and the praseodymium(Ⅲ) complex were subjected to X-ray diffraction studies. Thermal decomposition behavior of the lanthanum(Ⅲ) complex was also examined.

关键词： 4-aminoantipyrine acetylacetone lanthanides thermogravimetry X-ray diffraction rare earths

solid-state alloying of Al-Mg alloys by accumulative roll-bonding:Microstructure and properties

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Journal of Materials science & Technology 2022年第30期125卷 238-251页

作者： X.M.Mei Q.s.Mei J.y.Li c.L.Li L.Wan F.chen Z.H.chen T.Xu y.c.Wang y.y.Tan school of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China Key Laboratory of Hydraulic Machinery Transients(Wuhan University) Ministry of EducationWuhan 430072China school of Mechanical Engineering Wuhan Polytechnic UniversityWuhan 430023China

In this study,a novel solid-state alloying approach was adopted to fabricate Al-Mg alloys with high Mg contents(c_(Mg)) by accumulative roll-bonding(ARB)of Al and Mg elemental materials to ultrahigh *** results showed that the degree of alloying increased with the increase of ARB cycles and a supersaturatedα-Al solid solution accompanied with nanoprecipitates was formed in the Al-Mg alloys by ARB to 70 *** as-prepared Al-Mg alloys exhibited enhanced mechanical properties,with a maximum tensile strength of∼615 MPa and a tensile elongation of∼10%at c_(Mg)=13 wt.%.The high strength can be attributed to different mechanisms,namely solid solution strengthening,grain boundary strengthening,dislocation strengthening,and precipitation *** Al-Mg alloys showed increased work hardening with increasing c_(Mg),due to the enhanced formation of ***,no obvious drop in the intergranular corrosion(IGc)resistance was found in the Al-Mg alloys with c_(Mg) up to 13 wt.%.Moreover,sensitization treatment was found to induce little decrease in the IGc resistance of the Al-Mg alloys with c_(Mg)≤13 wt.%.We found that the excellent IGc resistance was due to the suppression of grain boundary precipitation by the preferred formation of precipitates within the grains that were induced by *** study indicated the novelty of the present solid-state alloying approach to achieving a superior combination of high mechanical properties and IGc resistance in Al-Mg alloys.

关键词： solid-state alloying Al-Mg alloys Mechanical properties IGc resistance ARB

Influence of Grain size and Texture on the yield Asymmetry of Mg-3Al-1Zn Alloy

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Journal of Materials science & Technology 2011年第1期27卷 29-34页

作者： s.M.yin c.H.Wang y.D.Diao s.D.Wu s.X.Li shenyang University of chemical Technology Shenyang 110142China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

The yield asymmetry between compression and tension of magnesium alloy Mg-3Al-1Zn（AZ31） with different grain sizes and textures has been studied by tensile and compressive testing of as-cast,as-extruded and equal channel angular pressed（EcAPed） *** significant yield asymmetry（the ratio of yield strength between compression and tension σyc/σyt is ～0.44） was found in as-extruded specimens and the corresponding microstructure evolution during deformation revealed that {10 ˉ 12} tensile twinning is the underlying reason for the large yield *** texture and grain size are influential factors for large yield *** separate contributions of grain size and texture on yield asymmetry were investigated.

关键词： Magnesium alloys yield asymmetry Texture Grain size Equal channel angular pressing(EcAP)

Influence of carrier Gas on Analysis of MgO Powders by Laser Ablation Inductively coupled Plasma Mass spectrometry

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Journal of Materials science & Technology 2009年第3期25卷 333-335页

作者： J.s. Lee y.s. Lee c.J. Park H.s. Lee D.s. Lee Department of chemistry Yonsei University Material Analysis Team Korea Testing Laboratory Korea Research Institute of standards and science school of Material science and Engineering Pusan National Univirsity

Laser ablation inductively coupled plasma mass spectrometry （LA-IcP-Ms） has been widely adopted for the direct multi-elemental analysis with high sensitivity. Especially analysis of fine ceramics by LA-IcP-Ms without time-consuming sample decomposition process has been one of the most expecting application field. small additive elements in MgO powders were analyzed by LA-IcP-Ms. For precise and accurate analysis influence of carrier gas （Ar or He） was presented by the signal intensities of IcP-Ms, relative standard deviation of signal intensities and ablated particle size distribution. Ablated particles were collected and analyzed by scanning electron microscopy （sEM） to investigate the particle size distribution, and the ablated sample surface was examined by camscope. In He gas atmosphere, the signal was more stable than in Ar gas atmosphere. The signal intensity was higher in Ar than in He. Examination of ablated particles and sample surface reveals that more particles were generated in Ar atmosphere and the distribution of particle size was larger.

关键词： Laser ablation MgO powders carrier gas IcP-Ms

structural and optoelectronic properties of sprayed sb:snO_2 thin films:Effects of substrate temperature and nozzle-to-substrate distance

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Journal of semiconductors 2011年第10期32卷 1-9页

作者： A.R.Babar s.s.shinde A.V.Moholkar c.H.Bhosale K.y.Rajpure Electrochemical Materials Laboratory Department of PhysicsShivaji University

The influence of substrate temperature and nozzle-to-substrate distance（NsD） on the structural,morphological, optical and electrical properties of sb：snO_2 thin films prepared by chemical spray pyrolysis has been *** structural,morphological,optical and electrical properties were characterized by using XRD,sEM, UV-visible spectrophotometry and Hall effect measurement *** was seen that the films are polycrystalline, having a tetragonal crystal structure with strong orientation along the（200） *** pyramidal crystallites formed due to coalescence were observed from sEM *** values of highest conductivity,optical transmittance and figure of merit of about 1449（Ω·cm）^（-1）,70%and 5.2×10^（-3）□/Ω,respectively,were observed for a typical film deposited using optimal conditions（substrate temperature = 500℃and NsD = 30 cm）.

关键词： substrate temperature NsD structural optoelectronic properties