Z.-J. Zhan

Technical Institute of Physics and Chemistry, Peping, Beijing, China

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Publications (30)43.92 Total impact

  • B. R. Sun · L. Qi · Z. J. Zhan
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    ABSTRACT: Hf44.5Cu27Ni13.5Ti5Al10 bulk metallic glasses were prepared by the copper mold casting process. The crystallization behaviors of the amorphous alloys treated at different isothermal annealing temperatures were investigated. The results indicated that the crystallization of the alloy proceeded by the process Am-0 (amorphous state) -> Am-1 + Al16Hf6Ni7 -> Am-2 + Al16Hf6Ni7 + Ti2Cu3 + Cu3Ti -> Am-3 + Al16Hf6Ni7 + CuTi2 -> CuHf2 + CuTi2. After annealing at 763 K, the sample displayed the highest fracture strength of 2401 MPa with an elastic strain of 3.0%. The nanoscale dimple structure and periodic stripes could be observed on the fracture surface. The spacing between stripes decreased gradually and eventually disappeared with the increase of the annealing temperature. (c) 2013 Elsevier B.V. All rights reserved.
    No preview · Article · Dec 2013 · Journal of Alloys and Compounds
  • Y.-T. Wen · H.-R. Wang · Y.-Y. Zhang · Z.-C. Wang · Z.-J. Zhan · B. Liang
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    ABSTRACT: During the electromagnetic launching process, the caliber of electromagnetic railgun may be expanded due to the electromagnetic force generated by the acute current. The caliber expansion has an effect on the repeated launch stability of the electromagnetic railgun. A novel high-speed linear array CCD measurement system was developed to detect this caliber expansion. The images obtained by the measurement system are analyzed using software methods. The results show that there is a linear relationship between caliber expansion and launching current, and the higher the launching current is, the larger the caliber expansion value is. The high-speed linear array CCD measurement system can measure the deformation of expanded caliber precisely in the sub-pixel dimension in a very short time.
    No preview · Article · Oct 2013 · Binggong Xuebao/Acta Armamentarii
  • Y.-P. Wang · B.-R. Sun · Z.-J. Zhan · W.-K. Wang
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    ABSTRACT: The quasi-static and dynamic compression tests for Hf 44.5Cu 27Ni 13.5 Ti 5Al 10 metallic glass were done by MTS810 and split Hopkinson pressure bar (SHPB) in the range of strain rate of 10 -4-10 3 s -1. The compressive stress-strain curves were obtained under varied strain rate and the fracture morphologies were studied by scanning electron microscopy. The experimental results show that the Hf 44.5Cu 27Ni 13.5 Ti 5Al 10 metallic glsaa does not have the strain rate sensitivity under quasi-static compression. The dimple structure and periodic corrugations with about 60 nm spacing can be observed at the fracture surfaces which consist of radical zone and fan-shaped zone. Under dynamic compression, the yield strength rapidly declines with rise of strain rate, the metallic glass has the strain rate sensitivity. The fracture surfaces show floccule structure with vein-like patterns. Further observation reveals that dynamic compression fracture surfaces exist three fracture morphology: branch-like patterns, vein-like patterns and molten agglomerates.
    No preview · Article · Jun 2012 · Gaoya Wuli Xuebao/Chinese Journal of High Pressure Physics
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    ABSTRACT: Railgun materials play an important role in electromagnetic launch, and its performance has great effect on the shot-efficiency and lifetime of the launcher. In this paper, the effect of shots number on the performance of multiple launch railgun material under high current conditions is studied by metallurgical analysis. The metallographys of kinds of rails' surface at various locations are observed, and the details of damage zones at different positions are analyzed. The results indicate that molten aluminum from the armature deposits on the rail surface to form a thin film. The deposited film becomes thicker and multi-layered with the increase of shots number. When the velocity is greater than 2 km/s, the gouge phenomenon always appears. The gouge volume of material is measured by 3D laser image and the qualitative observations of the damage are obtained. The evidences show that gouge phenomenon mainly causes by the kinetic energy of the armature and it is related to the shear strength of rail materials closely. By the addition of nano-sized ceramic powders, the shear strength of rail materials increases, the volume of gouge decreases during multiple launches.
    No preview · Article · Dec 2011 · Journal of Harbin Institute of Technology (New Series)
  • Y.-T. Wang · F.-X. Jiang · Y.-P. Wang · Z.-J. Zhan · W.-K. Wang
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    ABSTRACT: Hf44.5Cu27Ni13.5 Ti5Al10 bulk amorphous alloy was prepared by copper mold casting process, and then isothermal annealing treatment at different temperatures was carried out. Crystallization behavior of the amorphous alloy was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of isothermal annealing on mechanical properties of the alloy were studied by a MTS810 tester and field emission scanning electron microscopy (FESEM). The results indicate that the crystallization of the alloy proceeds by the process of Am(amorphous state) → Am+Al16Hf6Ni7 → Am+Al16Hf6Ni7+CuTi2 → CuHf2+CuTi2. The fracture strength of the alloy presents first increases, then decreases with the increase of annealing temperature. After annealing at 743 K, the fracture strength reaches the maximum value of 2400 MPa with elastic strain of 3.0%. The nanoscale dimples and periodic corrugations are observed on the fracture surface. The corrugation spacing decreases gradually and eventually disappears with the increase of annealing temperature. The fracture morphology is characterized by river shape pattern of brittle cleavage fracture.
    No preview · Article · Oct 2011 · Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment
  • R.G. Zheng · Z.J. Zhan · W.K. Wang
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    ABSTRACT: A new type Cu–La2O3 composite was fabricated by internal oxidation method using powder metallurgy. Sliding wear behavior of the Cu–La2O3 composites was studied by using a pin-on-disk wear tester under dry sliding conditions with or without electrical current, rubbing against GCr15 type bearing steel disk at a constant sliding speed of 20m/s. The influence of varying applied load and electrical current was investigated. The worn surfaces were examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) to determine the wear mechanisms. The results showed the Cu–La2O3 composites had an electrical conductivity of 81.9% IACS (International Annealed Copper Standard, 100% IACS=58MS/m) and a hardness of HV105. The wear rate of the Cu–La2O3 composite pins increased with the increase in the electrical current at high sliding speed. The main wear mechanisms of the Cu–La2O3 composites were found to be adhesive wear, abrasive wear and arc erosion.
    No preview · Article · Jan 2010 · Wear
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    ABSTRACT: Bulk metallic glasses (BMG) (Zr51.6Cu48.4)100-x Alx(x=6-10, molar fraction, %) were prepared by copper mould casting. The effect of Al content on the glass-forming ability (GFA) of ZrCu based metallic glass alloys was investigated by differential scanning calorimetry, X-ray diffractometry, and optical microscopy. The results show that when the Al content is 9.0%, the alloy has the optimal GFA. Proper Al additions can suppress the precipitation and the growth of the primary CuZr phase. The critical cooling rate of the Zr47Cu44Al9 alloy is about 10 K/s. The compression strength is about 1.9 GPa and the elongation is about 0.5%. The surface morphology of fracture shows a clear vein pattern.
    No preview · Article · Jan 2010 · Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals
  • B.-Q. Zhang · G.-H. Cao · Z.-J. Zhan · R.-P. Liu · W.-K. Wang
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    ABSTRACT: Zr47Cu44Al9 bulk metallic glass was prepared by copper mold casting. The crystallization behavior of the bulk metallic glass was investigated by using differential scanning calorimetry(DSC). The results show that the character temperatures, including glass transition temperature Tg, crystallization temperature Tx and crystallization peak temperature Tp, all move to high temperature zone with increasing of heating rate. The activation energy of glass transition, crystallization and peak crystallization are 390.2kJ/mol, 325.1kJ/mol and 299.5kJ/mol, respectively. The crystallization activation energy decreases with increase of the crystallizaed volume fraction. The results show that Zr47Cu44Al9 bulk metallic glass has good thermal stability.
    No preview · Article · Dec 2009 · Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment
  • C Yang · W P Chen · R P Liu · Z J Zhan · M Z Ma · W K Wang · X D Wang · Q P Cao · J Z Jiang · C Lathe · H Franz
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    ABSTRACT: Crystallization of Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) prepared by shock-wave quenching under high-temperature and high-pressure has been examined by in situ synchrotron radiation x-ray diffraction. The first precipitated phase is found to be the same at different pressures, but the subsequent phase precipitation sequences are different. The crystallization temperature of the BMG increases with pressure, but with a sudden drop at about 6.0 GPa. The different phase precipitation sequences and the sudden drop in the crystallization temperature can be explained by complex pressure effects on the atomic configuration of the BMG.
    No preview · Article · Nov 2007 · Journal of Physics Condensed Matter
  • C. Yang · W.-P. Chen · Z.-J. Zhan · J.-Z. Jiang
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    ABSTRACT: Phase evolution (PH) of Zr41Ti14Cu12.5Ni10 Be22.5 bulk metallic glass (BMG) prepared by shock-wave quenching has been studied under high-temperature and high-pressure using in situ synchrotron radiation energy-dispersive X-ray diffraction. The results show that the primarily precipitated phase is Zr2Be17 at applied pressures, but the subsequent PH processes are different. The crystallization temperature increases with pressure, but with a sudden drop at about 6.0 GPa. Compared with experimental results of the BMG prepared by water quenching, it can be concluded that crystallization temperature of the BMGs prepared by shock-wave quenching and water quenching all drop at the same pressure region, at which their PHs are different from those of other pressures. The different PHs and the drop of crystallization temperature may be attributed to that the BMG possesses different atomic configuration at different pressures.
    No preview · Article · Sep 2007 · Gaoya Wuli Xuebao/Chinese Journal of High Pressure Physics
  • L. Y. Zhang · Z.J. Zhan · Y. Z. Jia · W.K. Wang · B.D. Zhou
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    ABSTRACT: A novel fast cooling technology, melt-liquid-quenching (MLQ) with special cooling medium, was invented to prepare Al–7.0wt.%Si–0.4wt.%Mg alloys. The microstructure and mechanical properties of the alloy was investigated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), microhardness (HV) and tensile strength testing method. The DSC results showed that exothermal peak around 260°C of Al–7%Si–0.4%Mg alloys obtained by MLQ method is broader than that obtained by water-cooling copper mould (WCCM). When the specimens obtained by these two methods were aged at 260°C for 8h, no exothermal peaks were found. This demonstrated that, cooling rate of melt obtained by MLQ method is faster than that obtained by WCCM method. Microstructure of the castings obtained by MLQ was refined obviously and both microhardness and ultimate tensile strength (UTS) of the alloy were 33.3 and 22.9% higher than those made by WCCM, respectively.
    No preview · Article · Jun 2007 · Journal of Materials Processing Technology
  • Z.-J. Zhan · Q.-Y. Liu · R.-G. Zheng · W.-K. Wang · J. Liu
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    ABSTRACT: The knowledge of the equation of slate (EOS) and the compressibility of a solid are of central importance for the understanding of the behavior and the application of a condensed matter. The compression behavior of Zr41Ti14Cu12.5 Ni10Be22.5 bulk metallic glass (BMG) is investigated at room temperature up to 24 GPa using in-situ high pressure energy dispersive X-ray diffraction with synchrotron radiation. A model of basic cell volume has been established and the equation of state of BMG is determined by the calculation of radial distribution function. The experimental results indicate that the BMG contains a large amount of vacancy-like free volume. Low pressure (below 7 GPa) induces the collapse of the free volume to some extent and structure relaxation in the BMG.
    No preview · Article · Jun 2007 · Journal of Harbin Institute of Technology (New Series)
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    ABSTRACT: Compression behaviour and micro-structure evaluation of Zr57Nb5Cu15.4Ni12.6Al10 bulk metallic glass is investigated at room temperature up to 32.8 GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The equation of state of the bulk metallic glass is −ΔV/V=0.012P−2.49×10−4P2−9.5×10−7P3+5.02×10−8P4. The result shows that the nearest atom pair of the as-quenched bulk metallic glass corresponds to Zr–Zr correlations. And with pressure increasing, the nearest atom pair changes to a new one at 32.8 GPa.
    No preview · Article · May 2007 · Materials Letters
  • C. Yang · Z. J. Zhan · C. Z. Fan · R. P. Liu · W. K. Wang
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    ABSTRACT: Crystallization of Zr(41.9)Ti(14.7)Cu(13).(1)Ni(10.1)Be(20.2) (number indicate at.%) bulk metallic glasses prepared by shock-wave quenching and waterquenching are investigated by in situ X-ray diffraction under continuous heating conditions. Different phases and different precipitation sequences are found for both bulk metallic glasses. The differences in crystallization are probably attributed to different atomic configurations between the two bulk metallic glasses prepared by different ways. (c) 2006 Elsevier B.V. All rights reserved.
    No preview · Article · Mar 2007 · Materials Science and Engineering A
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    ABSTRACT: Phase transition cooling (PTC), using the absorbed latent heat during the melting of phase transition cooling medium to cool and solidify alloys in the process of casting, is a new fast cooling technology. Specimens of A356 casting aluminum alloy were prepared by this method. For comparison, specimens made by water-cooling copper mould (WCCM) were prepared too. The mechanical properties of A356 alloy made by PTC and WCCM were measured by microhardness and tensile strength testing methods. Microstructures of A356 alloy were investigated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-rays diffraction (XRD). The results show that both microhardness and ultimate tensile strength (UTS) of A356 alloy made by PTC method are much higher than those made by WCCM method. This can be attributed to the refined microstructure and the extended solubility of silicon in α-Al. The solubility of silicon in α-Al was 2.7at.% in specimens solidified in phase transition cooling medium and 2.4at.% in specimens solidified in water-cooling copper mould.
    Full-text · Article · Mar 2007 · Materials Science and Engineering A
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    ABSTRACT: The melt of casting Al-Si-Mg aluminum alloys was cast into the mold cooled by Sn, then bar shape samples with a diameter of 10 mm were prepared. Microstructure and mechanical properties of the alloy were studied. The results shows that, compared with water cooling copper mold, microstructure with grain size of 5 μm in diameter could be obtained by Sn-cooling copper mold technique, which was refined 37.5% than that made by water-cooling copper mold (8 μm); micro-hardness (HV) was improved 33.3% (Sn-cooling copper mold: 80 HV0.05; water-cooling copper mould: 60 HV0.05) and ultimate tensile strength (UTS) was improved 22.9% (Sn-cooling copper mold: 220 MPa; water-cooling copper mould: 179 MPa). Therefore, Sn-cooling copper mold technique could obviously refine microstructure, improve mechanical properties and have a potential prospect in practical applications.
    No preview · Article · Jan 2007
  • Q. Li · C.-Z. Fan · Y.-Z. Jia · L.-Y. Zhang · Z.-J. Zhan · W.-K. Wang
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    ABSTRACT: Considering the effect of current profile, a simple model was adopted to calculate the rail and armature joule heating of a small-scale electromagnetic rail gun after a single shot. The results indicate that the joule heating of copper rail is about 81. 5 kJ occupying 20% of the energy that put into the railgun system. Such thermal energy can heat the surface of copper rail to about 260 °C which is much lower than the melting point of copper (1 083 °C ). In the same way, the armature joule heating is about 991 J. The energy can heat the armature surface to about 260 °C which is less than the melting point of the aluminium-alloy(620 °C). The rail and armature of electromagnetic rail gun system will not melt after a single shot.
    No preview · Article · Dec 2006
  • C. Yang · R.P. Liu · Z.J. Zhan · L.L. Sun · W.K. Wang
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    ABSTRACT: High speed impact on Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) was realized by a two-stage light gas gun. Under planar shock wave at the impact velocity of 2.7 km/s, radial symmetric cracks formed on the shocked surface of the sample. Shear cracks/bands about 35° to the shocking direction and parallel to each other on the cross-section of the recovered sample were found in the layer subjacent to the shocked surface. Obvious traces of melting were shown inside the adiabatic shear cracks. Under spherical shock wave, crater profiles and lamination cracks were presented in addition to the adiabatic shear cracks/bands. The cracking of the BMG follows a process of nucleation, growth, and coalescence of micro-voids.
    No preview · Article · Jun 2006 · Materials Science and Engineering A
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    ABSTRACT: Crystallization of Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass under high temperature and high pressure has been investigated by in situ synchrotron radiation x-ray diffraction. The onset temperature of crystallization was found to increase with pressure, but with a sudden drop at about 5.6 GPa. Though the primarily precipitated phase is the same at different pressures, the sequences of the following phase precipitation are different.
    No preview · Article · Jan 2006 · Journal of Applied Physics
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    ABSTRACT: Planar shock compression effects on void formation and cracking in Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) are studied in this paper. Cracking was found to be a result of void linkage in some direction deviation from the maximum shear stress plane. Changing the state of the stress inside the BMG sample led to formation of different void distribution. Nucleation of the microvoids was possibly initiated by release of excess free volume under shock wave compression. (c) 2005 Springer Science + Business Media, Inc.
    No preview · Article · Jul 2005 · Journal of Materials Science