Papers by Author: Ping Liu

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Authors: Wei Li, Ping Liu, Feng Cang Ma, Xin Kuan Liu, Xiao Hong Chen, Yong Hua Rong
Abstract: A nanocrystalline surface layer is produced in Co plate by surface mechanical attrition treatment (SMAT). The characterization of microstructure and composition indicates that elements of Fe, Cr diffuse from hardened steel balls into the surface layer during SMAT. The diffusion phenomenon results in the composition deviation in the surface layer, leading to higher value of saturation magnetization (Ms) for nanocrystalline Co surface layer in comparison with its coarse-grained counterpart.
Authors: Feng Cang Ma, Ping Liu, Wei Li, Xin Kuan Liu, Xiao Hong Chen, Di Zhang
Abstract: In this paper, Ti-1100 composites reinforced with TiB+TiC ceramic particles were fabricated using in situ technologies. Mechanical properties of the composites with different volume fractions of TiB and TiC reinforcements were evaluated by tensile tests at 873K. The breakage of TiB was observed during the failure process of the composite. Strengthening efficiencies of the reinforcements for different composites were calculated. The strengthening mechanisms in this composite during tensile tests were discussed. It was suggested that the effect of the solution of C, which was produced in the preparation process, also can not be ignored for such a composite.
Authors: Xin Kuan Liu, Ping Liu, Yang Hui Xiang, Wen Bin Hu, Wen Jiang Ding
Abstract: The reconditioning operation of electroless nickel (EN) plating was studied and the influence of aging on the deposition speed, phosphorous content and stability of the operating solution was analyzed. The results showed that aging of the EN bath caused a dramatic declining of the deposition speed and the bath stability, while a slow increasing in phosphorous content of the deposit. Fluoride of NaF and NiF2 would precipitate from the bath due to the accumulation of sodium and fluorine ions during the replenishment. The sediment of NaF and NiF2 had a detrimental effect on the EN process and would deteriorate the protection of EN plating.
Authors: Dai Hua He, Qian Zhao, Chang Bao Wang, Hao Zhang, Xiao Run Zhang, Ping Liu, Xin Kuan Liu
Abstract: The bioceramic hydroxyapaptie (HA) is frequently used as coat in titanium medical implants improving bone fixation and thus increasing a lifetime of the implant. However, its joining to the titanium alloy is not satisfactorily good. The aim of this work is to produce TiO2 and HA gradient coatings on Ti6Al4V alloy to improve the interface joining. Compared the microstructures of cross section of Ti6Al4V-HA coating and Ti6Al4V-TiO2 /HA gradient coatings. HA coatings were obtained by sol-gel method with sol solutions prepared from calcium nitrate tetrahydrate and triethyl phosphate as the calcium and phosphorous sources. And TiO2 coatings were obtained from Tetra Butyl Titanate and absolute ethyl alcohol as the sources by sol-gel method too. The configuration and structure were investigated with scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The results demonstrated that the TiO2/HA gradient coatings have a homogeneous microstructure. The TiO2 coating made the HA coating adhere to the Ti-6Al-4V substrate well.
Authors: Yi Zhang, Bao Hong Tian, Ping Liu, Shu Guo Jia, Li Fan, Yong Liu
Abstract: The flow stress behavior of Cu-2.0Ni-0.5Si alloy during hot compression deformation was studied by isothermal compression test at Gleeble-1500D thermal-mechanical simulator.Dynamic recrystallization and dynamic recovery during high temperature deformation have been investigated by means of compression tests in the temperature and strain rate ranges of 873 to 1073 K and 0.01 to 5s-1 under maxium strain of 60%. The results show the flow stress was controlled by both strain rate and deforming temperature,the flow stress decreases with the increase of deforming temperature,while increases with the increase of strain rate.The hot deformation equation is e& = e28.47[sinh(0.013s )]5.52 exp(-245.4´103 / RT ) .
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