Nanchang Hangkong University

About: Nanchang Hangkong University is a education organization based out in Nanchang, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 7004 authors who have published 5270 publications receiving 62162 citations. The organization is also known as: Nanchang Aviation University.

α-Fe2O3 nanoparticles anchored on graphene with 3D quasi-laminated architecture: in situ wet chemistry synthesis and enhanced electrochemical performance for lithium ion batteries

Abstract: A novel α-Fe2O3/graphene composite is prepared by a simple in situ wet chemistry approach. The α-Fe2O3 particles with diameter around 130 nm are homogeneously anchored on graphene nanosheets to form a 3D quasi-laminated architecture. Such a well-organized flexible structure can offer sufficient void space to facilitate the electrolyte penetration, alleviate the effect of the volume change of α-Fe2O3 particles and avoid particle–particle aggregation during lithium insertion/desertion. In addition, graphene not only improves the electric conductivity of the composite electrode but also maintains the structural integrity of the composite electrode during long-term cycling. As anode material for Li-ion batteries, the α-Fe2O3/graphene composite electrode exhibits a stable capacity of 742 mAh g−1 up to 50 cycles. The synthesis technique is suitable for practical large-scale production of graphene-based metal oxide composites as advanced electrode materials for rechargeable Li-ion batteries.

Fabrication of CdSe Nanoparticles Sensitized Long TiO2 Nanotube Arrays for Photocatalytic Degradation of Anthracene-9-carbonxylic Acid under Green Monochromatic Light

Abstract: CdSe nanoparticles with well dispersion were decorated on inner and outer surfaces of 4 μm long TiO2 nanotubes through a simple direct current electrotechnique, resulting in a composite functional material with a perfect construction. The applied depositing voltage plays a determinative role during the CdSe nanoparticles formation process, getting through the breakdown potential of TiO2 and providing intense active sites for the CdSe crystal growth on the TiO2 nanotubes. The CdSe/TiO2 composite nanotube arrays exhibit high absorption in the visible light region due to the narrow band gap of CdSe, and depict sensitive photoelectrochemical response under visible light illumination. Photocatalytic degradation of anthracene-9-carbonxylic acid (ACA), one of the derivants of persistent organic pollutants (POPs), was successfully achieved on CdSe/TiO2 nanotubes when exposed to the 550 nm green monochromatic light.

Investigation of welding crack in micro laser welded NiTiNb shape memory alloy and Ti6Al4V alloy dissimilar metals joints

Abstract: Dissimilar metals of NiTiNb shape memory alloy and Ti6Al4V alloy with a same thickness of 0.2 mm were joined by micro laser welding. The effect of laser power on crack sensitivity of the weld was investigated. The results show that full penetrated welds are obtained when the laser power of 7.2 W is used, many cracks are observed in the weld. With increasing the laser power to 12 W, the number of all cracks and cracking width first increase and then decrease. By XRD analysis, three different kinds of Ti2Ni, NbNi3 and AlNbTi2 intermetallic compounds are found in the weld. According to the formation enthalpy and binary phase diagram, brittle Ti2Ni phase with more contents is existed in the weld due to final solidification, and which is the main reason of crack formation along with large stress concentration. Moreover, the welding cracks like the weld center longitudinal solidification cracks, weld metal toe transversal liquid cracks, heat-affected-zone hot cracks and crater cracks are classified in the laser welded joints. A brittle cleavage fracture with cleavage planes and river patterns in the joints is presented from the fracture surface.

Effect of overlap rate on recrystallization behaviors of Laser Solid Formed Inconel 718 superalloy

Abstract: The effect of overlap rate on the residual stress, recrystallization nucleation location and the distribution of recrystallized grains of LSFed Inconel 718 superalloy were investigated. It is found that the as-deposited microstructures with different overlap rates have the similar characteristics including that columnar grains grow along the deposition direction. The overlap area possesses higher residual stress compared with the inner-pass area, and the position of peak residual stress is closer to previous pass. The increase in the overlap rate will broaden the variation range of the residual stress. During heat treatment, the recrystallization nucleation first occurs in the overlap area with the lower overlap rate, and then expands to both overlap area and inner-pass area paralleling with the increasing of the overlap rate. Although the overlap rate is only one of basic factors in the Laser Solid Forming process, it plays an important role in controlling residual stress distribution, material microstructure and mechanical properties. The higher overlap rate adopted, the finer and the more evenly distributed grains could be obtained through recrystallization for LSFed Inconel 718 superalloy.