Search

Copyright of Journal of Chongqing Medical University is the property of Journal of Chongqing Medical University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The wear resistance of titanium alloy is poor, the preparation of amorphous alloy coating on the surface of titanium alloy moving parts is a choice to maintain the advantages of titanium alloy and improve its wear resistance. The microstructure and tribological behaviour of Ti-based bulk amorphous alloy before and after cryogenic-thermal cycling treatment were studied by XRD diffractometer, differential scanning calorimeter, SEM, friction and wear tester. The results show that after cryogenic-thermal cycling treatment, the titanium-based bulk amorphous alloy remains completely amorphous, and the relaxation enthalpy increases by 11%. After cryogenic-thermal cycling treatment, the average hardness of Ti-based amorphous alloy decreases from 6.84 GPa to 6.59 GPa and the average elastic modulus decreases from 118.70 GPa to 103.43 GPa, but the ratio of hardness to elastic modulus increases. The wear rate of titanium-based bulk amorphous alloy after cryogenic-thermal cycling treatment is reduced by about 10% under the load of 5 N and 10 N. Compared with TC4 alloy, the wear rate is reduced by 20% under 5 N load and 50% under 10 N load, respectively.TC4 alloy shows serious adhesive wear due to its low hardness. After cryogenic-thermal cycling treatment, the wear mechanism of titanium-based amorphous alloy is changed from abrasive wear of as-cast Ti-based amorphous alloy to the complex mechanism with abrasive, adhesive and oxidation wear. With the increase of load, adhesive wear decreases and abrasive wear is dominant.Generally, cryogenic-thermal cycling treatment is an effective way to improve the tribological properties of Ti-based bulk amorphous alloy.

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The mechanical anisotropy of shale is an important basic parameter for the study of in-situ stress, sidewall stability and hydraulic fracture propagation. In view of the limitations and low success rate for sample preparation in macro-scale tests, we chose clastic rocks and fragmentized blocks which were easily found as the subjects for micro-scale tests, and used continuous stiffness measurements to carry out the nano-indentation tests on the shale samples with horizontal bedding and vertical bedding. The test data were analyzed on three main mineral matrices which were identified by the classification rule of hardness. And the hardness and young's modulus of the shale clay matrix were calculated by contact stiffness measurements and the fracture toughness by energy method. The test results proved the reasonability and convenience of the classification rule of hardness in processing nano-indentation data. Shale clay matrix is anisotropic at the nano-scale while the mechanical parameters at the nano-scale are related to the bedding direction. The anisotropy of each mechanical parameter varies in intensity. The anisotropy of young's modulus is weak, while that of fracture toughness is strong. The fracture toughness with horizontal bedding is 80% of that with vertical bedding.

Cellular metal materials structure is a new type of porous metal material, it is made up by lots of metal hollow spheres（MHS）, and mechanical behavior research of the single metallic hollow sphere is the foundation of the whole material mechanical performance. The individual MHS with 2 mm to 3 mm outside diameter,10 μm to 40 μm thick walls with porosity were studied, and nano-indentation test, quasi-static uniaxial compression experiment and elastic compression test were performed on the metallic hollow spheres to get the Young’s modulus and hardness of the MHS and the material which was made up of the sphere, also single MHS compression deformation process and characteristics could be observed, finally simulated elastic stage of metallic hollow sphere by finite element software ABAQUS, analyzed the influence of the Young’s modulus of the whole MHS by porosity on thin wall, and result shows that with the porosity increasing, the elastic modulus of MHS will decrease, and present nonlinear distribution, it can be described the same format of a power law function as the relation of porosity with the porous thin wall.

Preparation of prepregs by hot melt method is generally involved the infiltration of resin. For the epoxy resin with a heterogeneous curing system, the preparation of large thickness prepregs may be affected by the uneven distribution of curing agent. A nanomechanical method was used to study the micro-mechanical uniformity of the resin matrix of the composites prepared by thin thickness glass fibre prepregs and the glass fibre reinforced composites prepared by resin vacuum suction technology. The results show that to the composites prepared by thin thickness prepregs, the resin exhibits good micro-mechanical uniformity, the nano-hardness and wear properties of the resin at the different regions of the composite cross-section have a good uniformity. The composites prepared by resin vacuum suction method exhibits obvious layered distribution, the particles of the curing agent and accelerator are enriched at the outer surface of the fiber layer. The resin at the outer layer of the fibre layer has higher nano hardness and wear resistance, while to the resin about 0.4mm inside the fiber layer, its hardness goes down, a very low nano hardness of the resin deeply inside the fiber layer is observed.

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rare Metal Materials & Engineering is the property of Northwest Institute for Nonferrous Metal Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)