Applied Mechanics and Materials Vols. 152-154

Abstract: Mechanical properties of Cu-based metallic glass matrix composites reinforced by ductile fugitive phases, synthesized by warm extrusion of gas atomized powders, has been investigated under the uniaxial compression condition at room temperature. The ductile fugitive phases are well distributed in the metallic glass matrix and enhanced macroscopic plasticity is observed due to the formation of multiple shear bands, initiated from the interface between ductile fugitive phase and metallic glass matrix, as well as their confinement between the reinforcements, stemming from the constrained plastic deformation of the reinforcing ductile phase.

Abstract: Light alloys, such as Aluminium or Titanium based alloys are frequently used in the aircraft industry. In the particular case of Ti alloys, they are usually commonly turned for obtaining strategic airships parts under rigorous quality requirements, in order guarantee the functionality of the workpiece design conditions. So, the analysis of the finishing quality of the turned pieces is essential in the quality control process. In this paper a study of the finishing quality of dry turned UNS R56400 Ti alloy has been achieved on the basis of the analysis of workpiece surface roughness, Ra, as a function of cutting parameters, such as feed and cutting speed. In parallel, a comparative analysis of the influence of the tool coating has been achieved. The obtained results have shown that coated tools cause a worse surface finishing quality.

Abstract: Two kinds of chitosan derivatives are made by adopting Schiff alkaline method and amino protonation method to modify the amino in chitosan. Deprotection to amino is conducted under the condition of both acidity and alkalinity. It turns out that these two kinds of methods can both be protective to amino in chitosan. And deprotection contributes to more convenience. Impurities brought by chitosan modified products made out of Schiff alkalinity method are lot. By means of deprotection, output of products is higher. Compared with Schiff Alkalinity method, the impurities brought by modified products made out of amino protonation method are lesser with a comparatively low productivity.

Abstract: New UV-thermal dual hybrid curable organosilicon-modified epoxy monoacrylates (OMEMA) were synthesized in this study. The changes of NCO groups during the synthesis process of OMEMA were measured by chemical titration method, and its Fourier Transform Infrared (FTIR) spectra were investigated. The results indicate that organosilicon chain segments can be grafted onto the epoxy monacrylates (EMA) by the reaction of NCO and OH groups. The FTIR of OMEMA show that it contains both double bond of acrylic ester (UV curable) and epoxy groups (thermal curable).

Abstract: The experiment has studied the mechanical properties effect of rare earth(RE)-7075 Al alloy＇s hot rolled sheet and cold rolled sheet coursing by two-step aging treatment. The hot rolled sheet and cold rolled sheet were analyzed by EDS(energy dispersive spectrometer), SEM(scanning electron microscope) and tested by Brinell Hardness tester, Computer-controlled electronic universal testing. The results shows that the synthetical mechanical properties of hot rolled sheet exceeds cold rolled sheet. The tensile strength is higher approximately 80MPa, elongation is larger approximately 3% and Brill hardness is bigger approximately 30HB after the two-step aging treatment.

Abstract: A composite heat source model composed of Gaussian surface heat source and rotational paraboloidal body heat source have been established to simulate the temperature field of 20mm TA15 titanium alloy. The results show that the simulated peak temperature of molten pool during surface focus welding is 3200°C, while the simulated peak temperature of molten pool during lower focus is 2700°C, and the whole surface temperature of surface focus welding is higher than that of lower focus welding, while the whole inner temperature of surface focus welding is lower than that of lower focus. The simulated temperature gradient in the direction of depth during surface focus welding is large, but the simulated temperature gradient in the direction of depth during lower focus welding is small. The simulated result was verified by the thermocouple and contrast of weld cross section morphology. The simulated thermal cycle curves are well consistent to the results tested by thermocouple, and there is a good consistency between the simulated molten pool morphology and the real weld morphology, they verify the accuracy of finite element model.

Abstract: The effect of various deformation degree and temperature on static recrystallization of 304 stainless steel during two-passes hot compression deformation with the strain rate of 0.1s-1 was investigated by use of Gleeble-1500D thermo-mechanical simulation. It is indicated that deformation degree is the most obvious factor to static recrystallization. Besides, the grain sizes after deformation were also measured by metallographic method. The results show that the grain sizes decreased dramatically with the conditions of deformation temperature (1050°C), holding time (30s) and total deformation degree (0.35). The result has provides the corresponding scientific basis for the quality forecast of 304 stainless steel during hot thermoplastic deformation.

Abstract: In order to eliminate the hazards made by traditional three acid polishing on the environment and human health, the polishing quality influence was studied, which was brought by the additives such as the oxidant, corrosion inhibitor and surfactant, the affect that actual situation acted on the polishing time and temperature was described at the same time, on this basis, the optimum process parameters was determined. Under this process conditions, the better polishing effect was obtained, the yellow smoke pollution in chemical polishing successfully resolved and problem of the economic cost brought by substitution of three acid polishing was settled, which will meet the needs of industrial production.

Abstract: A bolock copolymer of poly(ε-caprolactone) and hyperbranched polyglycidol (PCL-b-HPG) was synthezed by “living” copolymerization of ε-caprolactone (CL) and glycidol. The chemical structure was confirmed by 1H NMR, IR and GPC spectrum. Nanoparticles (NPs) of 50–100 nm were formulated from the PCL-b-HPG copolymer with no evidence of particles aggregation as determined by TEM. RGD peptide was covalently coupled on the end hydroxyl groups that could enable recepter–mediated recongnation onto targeted tissues. In conclusion, a hyperbranched copolymer PCL-b-HPG was synthezed by a novel and simple approach. The numerous functional end-groups could facilitate the attachment of biomolecules for further investigation as targeted drug delivery.

Abstract: It is indicated that the fluid flow does not abide by the Darcy law in certain low permeability reservoirs. The results of pressure date analysis in these low permeability reservoirs would be inaccurate when generalized using Darcy flow models. To improve analysis results, based on the concept of variable permeability effect, the dual non-Darcy coupling flow model is established in this paper. The iterative algorithm is adopted to solve the differential set of equations. This work also describes the pressure behaviors by pressure response curves.