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Hao X.,Beihang University | Zheng R.,Beihang University | Hao L.,Hebei Sitong New Metal Material co. | Yang H.,Beihang University | Ma C.,Beihang University
Materials Science Forum | Year: 2013

Nanocrystalline (NC) Al alloy powder was fabricated by milling 2024 Al alloy powder andFe-based metallic glass (FMG) particles. The NC Al alloy powder was consolidated into bulk sampleby adding a part of atomized coarse-grained (CG) 2024 alloy powder. The microstructure andmechanical properties of powder and consolidated bulk materials were examined by X-RayDiffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy(TEM) and mechanical test. It revealed that the FMG particles were uniformly distributed in the NCaluminum alloy powder. In the consolidation process, the grain size increased, and Al2CuMg phaseprecipitated. The multi-modal Al alloy by consolidation of FMG particles, NC and CG powder,exhibited higher yield strength up to 517 MPa and better plasticity in comparison to the sampleswithout CG powder. © (2013) Trans Tech Publications, Switzerland.


Wang X.-J.,Beihang University | Xu C.,Beihang University | Muhammad A.,Beihang University | Hanada S.,Tohoku University | And 3 more authors.
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2014

To investigate the effects of Al-Ti-B-RE grain refiner on microstructure and mechanical properties of Al-7.0Si-0.55Mg (A357) alloy, some novel Al-7.0Si-0.55Mg alloys added with different amount of Al-5Ti-1B-RE grain refiner with different RE composition were prepared by vacuum-melting. The microstructure and fracture behavior of the Al-7.0Si-0.55Mg alloys with the grain refiners were observed by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), and the mechanical properties of the alloys were tested in mechanical testing machine at room temperature. The observation of Al-Ti-B-RE morphology and internal structure of the particles reveals that it exhibits a TiAl3/Ti2Al20RE core-shell structure via heterogeneous TiB2 nuclei. The tensile strength of Al-7.0Si-0.55Mg alloys with Al-5Ti-1B-3.0RE grain refiner reaches the peak value at the same addition (0.2%) of grain refiner. © 2014 The Nonferrous Metals Society of China.


Xu C.,Beihang University | Du R.,Beihang University | Wang X.-J.,Beihang University | Hanada S.,Tohoku University | And 3 more authors.
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2014

Al-1.0%Sc-1.0%Zr (mass fraction) master alloy was prepared at different cooling rates. The morphology and thermodynamics data of the primary particles of the master alloy were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). It shows that the primary particles are dendrite-shaped particles comprised of several attached small cubic, cusped-cubic or crucifer shape particles at slow cooling rate. However, the primary particles are separated with crucifer shape at intermediate cooling rate, and they are cubic with cusped-cubic shape at high cooling rate. Meanwhile, the separated and attached particles present Al 3Sc/Al3Zr1-xScx core-shell structure. The formation mechanism of the structure was systematically investigated by a mathematical model. © 2014 The Nonferrous Metals Society of China.


Zheng Y.,Beihang University | Xiao W.,Beihang University | Ge S.,LiZhong Group | Zhao W.,Hebei Sitong New Metal Material Co. | And 2 more authors.
Journal of Alloys and Compounds | Year: 2015

The microstructure and tensile properties of Al-Si-Cu-Mg alloys with different Cu contents and Cu/Mg ratios were investigated. The results show that the Mg2Si, θ-Al2Cu and Q-type intermetallic phases form in the as-cast Al-Si-Cu-Mg alloys depending on the Cu content and the Cu/Mg ratio. The Mg2Si is formed in the relatively low Cu/Mg ratio of alloy, while high Cu/Mg ratio promotes the formation of θ-phase and Q-phase. With the same Cu/Mg ratio, the high content of Cu and Mg elements simultaneously enhances the formation of θ-phase and Q-phase. Microstructural observation from the T6 tempered alloys reveals that the Cu content and the Cu/Mg ratio control the dissolution of primary intermetallic phases and the formation of precipitates, thus affecting the strength and the ductility. It is indicated that by controlling the Cu and the Cu/Mg ratio, the Al-6Si-2Cu-0.5Mg aged alloy with few primary compounds and a large number of fine Q′ precipitates exhibits high strength and acceptable ductility. © 2015 Elsevier Ltd. All rights reserved.


Xu C.,Beihang University | Xiao W.,Beihang University | Zhao W.,Hebei Sitong New Metal Material Co. | Wang W.,Hebei Sitong New Metal Material Co. | And 3 more authors.
Journal of Rare Earths | Year: 2015

The Al-5Ti-0.2C-based grain refiners with different contents of rare earth (RE) were successfully prepared via powder metallurgy and vacuum casting. The microstructural evolution has been studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the RE addition resulted in the formation of TiAl3/Ti2Al20RE core-shell structured primary particles, and the size of TiAl3 core decreased, while the thickness of Ti2Al20RE increased with increase of RE contents. As compared to Al-5Ti-0.2C grain refiner, the grain refining efficiency was gradually improved with increase of RE contents, which was mainly attributed to the TiAl3/Ti2Al20RE core-shell structured primary particles and insoluble TiC nuclei formed in a-Al matrix. The formation mechanism of core-shell structure was further investigated based on Ginstling-Brounstein model. © 2015 The Chinese Society of Rare Earths.


Yuan Y.B.,Science 37 | Zheng R.X.,Science 37 | Ge S.J.,Hebei Sitong New Metal Material co. | Yang H.,Science 37 | Ma C.L.,Science 37
Materials Science Forum | Year: 2013

Al86Ni7Y4.5Co1La1.5 (at.%) alloy powder was produced by argon gas atomization process.After high-energy ball milling, the powder was consolidated and extruded by using vacuum hotpress sintering under different process conditions, sintering temperature, extrusion pressure,sintering time, etc. The microstructure and morphology of the powder and consolidated bulk alloywere examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmissionelectron microscopy (TEM). The phase transformation of the powder was investigated bydifferential scanning calorimetry (DSC). Mechanical properties of the consolidated bulk alloy wereexamined. The results showed that as the milling time increase, the volume fraction of amorphousmaterials and the hardness and yield strength of the bulk alloy were obvious improved. © (2013) Trans Tech Publications, Switzerlan.


Wang H.,Southwest University of Science and Technology | Liu J.-Y.,Southwest University of Science and Technology | Yan W.-Q.,Southwest University of Science and Technology | Yan W.-Q.,Hebei Sitong New Metal Material Co. | And 3 more authors.
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2011

Using alkaline metal carbonate matrix and Eu3+ as luminescent center, a series of MCO3:Eu3+(M=Ca, Sr, Ba)red phosphor powder was synthesized by microwave assisted co-precipitation method. The spectrum properties, morphology, structure and particle size were characterized by photoluminescence and photo- luminescence excitation (PL-PLE) spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared pectrophotometer (IR) and laser diffraction particle size analyzer, respectively. The results showed that Charge Transfer Belt (CTB) gradually redshift with as the M2+ radius increasing. In 393 nm excitation, 614 nm emission intensity with the increase of M2+ radius enhanced first, then slashed. Luminous intensity of SrCO3:Eu3+ is the largest. Eu3+ as luminous center fully come into the MCO3 matrix crystal lattices. CaCO3:Eu3+ had spherical structure, reunion was serious; SrCO3:Eu3+ had smooth surface and spherical structure, the dispersion was very good, no reunion phenomenon; BaCO3:Eu3+ had micro needle-like structure.


Liu J.-Y.,Southwest University of Science and Technology | Yan W.-Q.,Southwest University of Science and Technology | Yan W.-Q.,Hebei Sitong New Metal Material Co. | Kang M.,Southwest University of Science and Technology | And 3 more authors.
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2011

SrCO 3:Eu 3+ precursor was synthesized through microwave asssisted co-precipitation method, then the SrCO 3:Eu 2+ phosphor was obtained by high temperature reduction process. The structure and luminescence properties of the SrCO 3:Eu 2+ were analyzed by XRD and PL-PLE. The results showed that the best sintering temperature was 1100°C and the optimum content of boric acid was 15%. In addition, the excitation spectrum of the SrCO 3:Eu 2+ phosphor was consisted of two broad bands at 220-320 nm and 400-580 nm, and the emission spectrum was located at 550-700 nm. It's characteristic emission peak was at about 610 nm (λ ex=475 nm), which belong to red fluorescence. This strontium carbonate matrix phosphor which have broadband excitation and emission could be used for manufacturing fluorescent glass.


Dai W.,Purdue University | Wang X.,Purdue University | Zhao W.,Hebei Sitong New Metal Material Co. | Han Q.,Purdue University
TMS Light Metals | Year: 2014

Al-Ti-B grain refiners are used by aluminum alloy casting manufacturers to reduce the grain size of castings. Both Al-5Ti- 1B and AI-3Ti-1B are common Al-Ti-B grain refiners that are produced by several grain refiner manufacturers. The grain refining effectiveness with respect to time of four Al-5Ti-1B refiner samples from four grain refiner manufacturers and two Al- 3Ti-lB refiner samples from two manufacturers was tested on commercial purity aluminum. Among the same type of grain refiners, the result of comparing grain refining efficiency from different grain refiner makers has been discussed in this paper. The composite particles of the grain refiner samples were observed by SEM and analyzed in an attempt to approach and understand the result of grain refinement under stirring. Copyright © 2014 by The Minerals, Metals & Materials Society.


Chen S.,Hebei Sitong New Metal Material Co. | Ma T.,Hebei Sitong New Metal Material Co.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2015

Al-Ti-B master alloys were fabricated by aluminothermic reaction, which were then improved by multiple melt holding treatment. The microstructure of the master alloy and refining mechanism were described using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the grain refining efficiency of Al-Ti-B master alloys is improved greatly by multiple melt holding treatment. After purification treatment, TiAl3 and TiB2 particles are refined to 20 μm and 1 μm, respectively. As compared with un-treated Al-Ti-B master alloy, the Al-Ti-B master alloy under multiple melt holding treatment can decrease grain size of pure aluminium from 344.6 μm to 216.5 μm. ©, 2015, Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys. All right reserved.

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