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Zhang J.M.,University of Science and Technology of China | Cai H.,University of Science and Technology of China | Sun W.C.,University of Science and Technology of China | Cai P.H.,Shaanxi Hande Axle Co.
Materials Science Forum | Year: 2015

The growth of microarc oxidation (MAO) coatings on aluminum substrates was controlled via changing solution temperature from 10 to 60 ℃. The results show that an elevation of the temperature lowers the applied voltage and the coating thickness. The coating formed in low-temperature solution demonstrates large-sized pores and contains lots of elements only originating from solute such as P, W, and V. On the contrary, numerous small-sized pores disperse homogeneously on the coating synthesized in high-temperature solution. It is assumed that the variation of solution temperature affects the dissolving capacity of the alkaline solution and the adsorptive capacity of solute anions, thus dominating the growth behaviors of MAO coating. © (2015) Trans Tech Publications, Switzerland.

Cai H.,University of Science and Technology of China | Sun W.C.,University of Science and Technology of China | Zhang J.M.,University of Science and Technology of China | Cai P.H.,Shaanxi Hande Axle Co.
Materials Science Forum | Year: 2015

Area-selectively liquid-phase-sintering (AS-LPS) method was developed to control the coarsening of Si particles in Al/60vol.% Si composites with the help of sol-gel-derived interfacial modification, achieved by pre-coating discontinuous Al2O3 film on Si powders. The results show that due to the local presence of less than 1 μm-thick films, Si particles can approximately preserve their as-received size and morphology after being sintered at 950 °C. Whereas, for those prepared by use of the unmodified Si powders, Si phases evolve to several hundred-micron-sized flakes, being similar to the typical eutectic Si in Al-Si casting alloys. It is assumed that the Al2O3-film-coated areas at Al/Si interface control the dissolution of Si into Al liquid, while in uncoated areas Al matrix and Si particles bond together by LPS, thus realizing AS-LPS. © (2015) Trans Tech Publications, Switzerland.

Guo F.,Xian Jiaotong University | Dong G.,Xian Jiaotong University | Dong L.,Shaanxi Hande Axle Co.
Applied Surface Science | Year: 2014

For the artificial hip joints, passive film formed on the Co-Cr-Mo alloy acted as a highly protective barrier in the body fluid. But its stability, composition and structure always influenced the protection. In this work, passive film was obtained by high temperature treatment. The effect of passivation environment on the properties of the passive film was investigated. The film's surface roughness, micro-hardness and structure were analyzed. In order to study the tribological behavior of the passive film, pin-on-disk tribotest was carried out under bovine serum albumin (BSA) and saline solution. Results indicated the sample passivated in vacuum had friction coefficient of 0.18 under BSA solution and 0.53 under saline solution; the sample passivated in air had friction coefficient of 0.14 under BSA solution and 0.56 under saline solution. In addition, the reference sample without passivation was tested under the same condition. It showed friction of 0.22 under BSA solution and 0.45 under solution. The lubricating mechanism was attributed to BSA tribo-film absorption on the surface and high hardness passive film. © 2014 Elsevier B.V.

Zhang L.-J.,Xian Jiaotong University | Zhang G.-F.,Xian Jiaotong University | Ning J.,Xian Jiaotong University | Zhang X.-J.,Xian Jiaotong University | And 2 more authors.
Materials and Design | Year: 2015

Laser welding of highly reflective materials, such as copper, has suffered problems such as spatter, underfill and undercut for a long time. This work analyzed the associated mechanism and suggested that appearance and integrity of laser welded copper joint could be improved by conducting the welding process at a high welding speed which is slightly below the critical welding speed for full-penetration welding at the specified laser power. The microstructure, mechanical properties and electrical conductivity of the T2 copper joint achieved under high welding speed were tested. Results show that copper joint and base material (BM) have similar electrical conductivity, the weld fusion zone (FZ) and the heat affected zone (HAZ) are softened; the tensile strength and elongation of the joint are approximately 20% and 84% below those of the BM respectively. The joint breaks near the interface between the longitudinal columnar grain structures (LC) growing along welding direction at the FZ center, and the horizontal columnar grain structures (HC) growing perpendicular to the welding direction at other area of FZ. Degradation of the mechanical properties of copper joint is attributed to the softening of the heated zone and the big angle between the growth directions of LC and HC. © 2015 Elsevier Ltd.

Shaanxi Hande Axle Co. | Date: 2010-04-13

Axles of automobiles; axles for land vehicles; axles for motor vehicles; hubs for vehicle wheels; land vehicle chassis; motor vehicle chassis; brake segments for land vehicles; brake segments for motor vehicles; non-skid devices for vehicle tires, namely, chains for vehicles, anti-skid textile covers for tires; lorries; trucks; wagons; sports cars; automotive wheel hubs.

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