Time filter

Source Type

Butt M.S.,Nanjing Southeast University | Butt M.S.,Jiangsu Key Laboratory for Advanced Metallic Materials | Bai J.,Nanjing Southeast University | Bai J.,Jiangsu Key Laboratory for Advanced Metallic Materials | And 7 more authors.
Materials Science and Engineering C | Year: 2017

Full biodegradable magnesium alloy (AZ31) strengthened poly-lactic acid (PLA) composite rods for potential application for bone fracture fixation were prepared by plastic injection process in this work. Their surface/interfacial morphologies, mechanical properties and vitro degradation were studied. In comparison with untreated Mg rod, porous MgO ceramic coating on Mg surface formed by Anodizing (AO) and micro-arc-oxidation (MAO)treatment can significantly improve the interfacial binding between outer PLA cladding and inner Mg rod due to the micro-anchoring action, leading to better mechanical properties and degradation performance of the composite rods.With prolonging immersion time in simulated body fluid (SBF) solution until 8 weeks, the MgO porous coating were corroded gradually, along with the disappearance of original pores and the formation of a relatively smooth surface. This resulted in a rapidly reduction in mechanical properties for corresponding composite rods owing to the weakening of interfacial binding capacity. The present results indicated that this new PLA-clad Mg composite rods show good potential biomedical applications for implants and instruments of orthopedic inner fixation. © 2016 Elsevier B.V.


Wan X.-F.,Nanjing Southeast University | Sun Y.-S.,Nanjing Southeast University | Sun Y.-S.,Jiangsu Key Laboratory for Advanced Metallic Materials | Xue F.,Nanjing Southeast University | And 4 more authors.
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2010

As-cast microstructure and mechanical properties of Mg-6Zn-2Al-0.3Mn (ZA62) alloys with calcium addition were investigated. The as-cast microstructure of the base alloy ZA62 consists of the a-Mg matrix and eutectic phase Mg 51Zn20. The Mg51Zn20 eutectic was gradually replaced by MgZn phase and Mg32(Al,Zn)49 phase when calcium is added into the base alloy. Further addition of calcium leads to the increase of grain boundary phases and formation of a new quaternary Mg-Zn-Al-Ca eutectic compound. In comparison with the base alloy, the increase of calcium addition to the base alloy results in the reduction of both strength and ductility at ambient temperature, but increase at elevated temperatures due to the thermal stability of Ca-containing phases. At elevated temperatures, the creep resistance of ZA62 based alloys containing calcium is significantly higher than that of AZ91 which is the most commonly used magnesium alloy. © 2010 The Nonferrous Metals Society of China.


Liu H.,Nanjing Southeast University | Liu H.,Jiangsu Key Laboratory for Advanced Metallic Materials | Xue F.,Nanjing Southeast University | Xue F.,Jiangsu Key Laboratory for Advanced Metallic Materials | And 5 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2014

The microstructures and the mechanical properties of the Mg-2Y-xZn (x = 1, 2, 3 at%) alloys in as-cast, as-annealed and as-extruded conditions have been investigated. The results show that the 18R-LPSO phases are distributed in a continuous network mainly along the grain boundaries in the alloy with 1 at% Zn. With increasing of Zn content, the 18R-LPSO phase and W-phase coexist in Mg-2Y-2Zn alloy but only W-phase remains in Mg-2Y-3Zn alloy. The 14H-lamellas are precipitated from the block-shaped 18R-LPSO phases into the matrix, and W-phases are broken into particles during homogenizing annealing. After extrusion, the LPSO phases and W-particles are rearranged along the direction of extrusion. The tensile tests show that the as-extruded Mg-2Y-1Zn alloy exhibits the supreme UTS of 320 MPa, with an elongation of 11.2% at room temperature. Copyright © 2014, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.


Li H.,Nanjing Southeast University | Li H.,Jiangsu Key Laboratory for Advanced Metallic Materials | Xue F.,Nanjing Southeast University | Xue F.,Jiangsu Key Laboratory for Advanced Metallic Materials | And 6 more authors.
Powder Technology | Year: 2016

Beta-tricalcium phosphate (β-TCP) was obtained by calcining the precursor calcium deficient hydroxylapatite (CDHA). The CDHA was synthesized via direct precipitation method using calcium hrdroxide and phosphoric acid assisted with polyethylene glycol ((CH2CH2OH)n; PEG). The X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermogravimetry-differential scanning calorimetry (TG/DSC), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to investigate the phase composition and morphology of obtained powders. The results showed that the PEG played an important role on improving the purity and dispersity of β-TCP. The size of β-TCP particles with nearly spherical shape was in the range of 0.2-0.5 μm when the CH2CH2O/H+ molar ratio was equal to 1:17. According to the TG/DSC, the formation of the β-TCP from the CDHA phase was about 770 °C. Meanwhile, a plausible synthetic mechanism has been proposed. © 2016 Elsevier B.V.


Zhao W.,Nanjing Southeast University | Wu Q.,Jiangsu Key Laboratory for Advanced Metallic Materials | Hao Q.,Jiangsu Key Laboratory for Advanced Metallic Materials | Wang J.,Jiangsu Key Laboratory for Advanced Metallic Materials | And 5 more authors.
Applied Physics Letters | Year: 2016

The excitation of plasmon in metallic nanostructures produces intense and strongly localized near fields that enhance light-matter interaction. Here, we report plasmon-phonon coupling in monolayer WS2 deposited with gold and silver nanoparticles. The Raman spectra reveal phonon modes arising from the coupling between plasmon and WS2. The localized surface plasmon resonance mediated excitation activates the Raman process without requiring defect for momentum conservation. Our results also reveal that the momentum induced by localized surface plasmon resonances losses to WS2 and the metal atoms adsorption modulated spin-orbit split are the two essential elements for the observed plasmon-phonon coupling. This work will open up exciting prospects for plasmon-phonon coupling in two dimensional systems. © 2016 AIP Publishing LLC.


Ni Z.,Nanjing Southeast University | Sun Y.,Nanjing Southeast University | Sun Y.,Jiangsu Key Laboratory for Advanced Metallic Materials | Xue F.,Nanjing Southeast University | And 3 more authors.
Jinshu Xuebao/Acta Metallurgica Sinica | Year: 2010

TiC dispersion-strengthened 304 stainless steel was fabricated using the technique of in situ reaction during melting of the steel. Microstructure observation reveals that the distribution of the added TiC particles with the size of 3-10 μm is basically uniform in the matrix grains, but slight aggregation of particles is observed in a few areas in the microstructure. The addition of TiC particles into 304 stainless steel results in the increase of ultimate strength, but the decrease of ductility. When the ingot of the TiC dispersion strengthened 304 stainless steel prepared is remelted by the technique of electroslag remelting, TiC particles in the steel are significantly refined and the distribution of them becomes more homogeneous, therefore the tensile properties of the steel are further improved in comparison with that before electroslag remelting. Some tiny TiC particles with nano-scale were observed in the microstructure of the steel after electroslag remelting. Introduction of TiC particles to 304 stainless steel also causes a notable increase in creep resistance at thtemperature of 650°C and applied stress of 150 MPa and the further improvement on creep properties of the steel is obtained after electroslag remelting. ©.


Wan X.,Nanjing Southeast University | Sun Y.,Nanjing Southeast University | Sun Y.,Jiangsu Key Laboratory for Advanced Metallic Materials | Xue F.,Nanjing Southeast University | And 4 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2010

The effects of trace Ca addition on microstructure and high-temperature creep resistance of as-cast Mg-12Zn-4Al-0.3Mn alloy were investigated. Results show that the as-cast microstructure of the base alloy consists of α-Mg matrix and block quasicrystalline phase at gain boundaries. The composition of this quasicrystalline phase is closed to that of the equilibrium τ phase (Mg32 (Al, Zn)49) in the Mg-Zn-Al ternary system. A small amount of Ca addition to the base alloy results in the formation of a lamellar eutectic φ (Al2Mg5Zn2) and the transformation of the quasicrystalline phase to the equilibrium phase in the as-cast microstructure of the alloy. The volume fraction of the φ phase increases with the increase of Ca addition. The creep resistance of the alloys is significantly improved by Ca addition. The optimum creep resistance of the alloy is obtained by 0.6% Ca addition under the creep condition of 175°C, 70 MPa, whose steady state creep rate is approximately one order of magnitude lower than that of its base alloy. © 2010, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.


Bai J.,Nanjing Southeast University | Bai J.,Jiangsu Key Laboratory for Advanced Metallic Materials | Sun Y.,Nanjing Southeast University | Sun Y.,Jiangsu Key Laboratory for Advanced Metallic Materials | And 3 more authors.
Materials Science and Engineering A | Year: 2012

The microstructures, mechanical properties and creep resistance of Mg-4Al-(1-4) La alloys produced by permanent mold casting and high pressure die casting (HPDC) were investigated. In addition to solute atoms in α-Mg matrix, Al element may exist in the form of three different intermetallic phases in the present alloys depending on the experimental conditions. In both casting states, the increase of La addition results in a rise in the volume fraction of Al 11La 3 eutectic, and simultaneously Mg 17Al 12 phase, including divorced eutectic in as-cast state and discontinuous precipitation after creep, is suppressed until completely disappears. This leads to a gradual increase in creep resistance. The formation of more Mg 17Al 12 phase in HPDC alloys is considered a major factor in causing their worse creep properties by comparison with that of the permanent mold casting alloys when La content is in a lower level below 2wt.%. By contrast, the HPDC alloys show better creep resistance with La content added above 2wt.% owing to the formation of denser network distribution of Al 11La 3 phase along grain/dendrite boundaries as a result of more rapid solidification rate and higher solidification pressure. For the alloys studied, grain/dendrite boundary sliding is suggested to be a possible controlling mechanism responsible for creep deformation at elevated temperatures. © 2012 Elsevier B.V.


Liu H.,Nanjing Southeast University | Liu H.,Jiangsu Key Laboratory for Advanced Metallic Materials | Xue F.,Nanjing Southeast University | Xue F.,Jiangsu Key Laboratory for Advanced Metallic Materials | And 2 more authors.
Advanced Materials Research | Year: 2011

The effects of fluxes with different activators (sebacic acid and diethylamine hydrochlcoride) on the wetting behavior of Sn-Zn lead-free solders were investigated. The wettability tests showed that fluxes with the addition of single sebacic acid or diethylamine hydrochlcoride significantly improved wettability of Sn-Zn solder on Cu substrate. However, fluxes with combined additions of above activators promoted wetting performance of the solder further. Thermal analysis (thermal-gravimetry analyzer and differential scanning calorimeter) results demonstrated that the effective temperature range of diethylamine hydrochlcoride is higher than that of sebacic acid. So diethylamine hydrochlcoride could react with oxides on the solder and substrate surfaces at a wider temperature range which resulted in an enhanced spreading of solders. Scanning electron microscopy (SEM) image showed that two kinds of diffusion layers were formed between Sn-Zn solder and Cu substrate, indicating fluxes with binary activators markedly improved welding quality of Sn-Zn solder. © (2011) Trans Tech Publications.


Ni Z.,Nanjing Southeast University | Sun Y.,Nanjing Southeast University | Sun Y.,Jiangsu Key Laboratory for Advanced Metallic Materials | Xue F.,Nanjing Southeast University | And 4 more authors.
Materials and Design | Year: 2011

Austenitic stainless steel reinforced with 5 vol.% TiC particulate was in situ synthesized by in situ reaction during melting process successfully and its microstructure, mechanical properties as well as oxidation behavior were investigated. Microstructure observations revealed that in situ TiC particulates with an average size of 2-10. μm distributed uniformly in the matrix and the interface boundaries between TiC particulates and austenite matrix were clean without any impurities and contaminations. Addition of TiC particulates refined the grain structure of austenitic matrix, but did not cause formation of any new phases in microstructure. Beneficial effects of TiC addition to austenitic stainless steel on both mechanical properties and oxidation resistance were found. Both at ambient and elevated temperature, tensile strengths of the steel with TiC addition were notably higher than those of its matrix alloy, however, a decrease in ductility also appeared, as exhibited by other particulate reinforced alloys. Besides tensile strengths, creep resistance of austenitic stainless steel was also significantly increased by TiC addition at elevated temperature of 923 K. Oxidation test at 1073 K revealed that TiC addition to austenitic stainless steel raised the oxidation resistance of the steel remarkably. © 2010 Elsevier Ltd.

Loading Jiangsu Key Laboratory for Advanced Metallic Materials collaborators
Loading Jiangsu Key Laboratory for Advanced Metallic Materials collaborators