Applied Mechanics and Materials Vols. 117-119

Abstract: The effects of Ca on the mechanical properties of Mg-6Zn-3Al alloy have been investigated. The results show that the addition of 1wt.% Ca can refine the grains, improve the microstructure, cause the formation of Al₂Ca phase, and enhance the mechanical properties of Mg-6Zn-3Al alloy at room temperature and 150°C.

Abstract: Si-doped lithium zirconate Li₂Si_xZr_(1-x)O₃(0≤x≤0.4) sorbents were prepared by a solid-state reaction method from nano-sized monoclinic ZrO₂. The morphology phase, structure and adsorption properties of the prepared lithium zirconate were respectively determined by using scanning electron microscope (SEM) , X-ray diffraction (XRD) and thermogravimetric analyzer (TG).The results showed the CO₂ adsorption properties of material could be improved by doping suitable amount Si.

Abstract: In this paper, a new pH/temperature sensitive hydrogel bead (HME) with core-shelled structure as a drug delivery system was prepared using N-acryloylglycinate and sodium alginate. In caffeine release studies, the effect of different pH value, temperature and the polymer content were evaluated, respectively. The results showed that 62.2% drug was released from the sensitive beads in pH 2.1 within 300 min, whereas 99.3% drug diffused into the medium in pH 7.4 at 37°C. The significantly higher release was observed at higher temperature than at lower temperature. In addition the release amount of drug was decreased with increasing polymer content. The release behaviors of caffeine suggested a feasibility of the beads as pH/thermo-controlled drug release carrier.

Abstract: Based on an explicit van der Waals (vdW) model, which can reproduce the interaction between any two layers of multi-walled carbon nanotube (MWCNT) and is dependent on the change of interlayer spacing and on the tube radii, the vibration analysis of multi-walled carbon nanotubes is carried out by using of the multi-layered Flugge shells model. The natural frequencies are analyzed in detail for with various radii and number of tubes. Furthermore, the natural frequencies of double-walled carbon nanotube with the innermost radii of 0.6 nm predicted based on the Flugge shell model are well compared with those from the Donnell shell one. The present investigation will be meaningful for the design and application of multi-walled carbon nanotubes as nano- resonators.

Abstract: ZnO microsphere with aperture were synthesized using pure Zn powder as templates via thermal evaporation methods. X-ray diffraction pattern shows the change of crystal structures from Zn to ZnO. SEM and TEM images show that the samples prepared at low gas pressure have hollow ZnO microsphere with aperture. Compared with the morphologies of samples synthesized at high gas pressure, the growth mechanism of hollow ZnO microsphere with aperture is presumed in detail. The experimental results indicate that the evaporation of Zn inside the ZnO microsphere shell prompts the formation of hollow microsphere, and that the high pressure induces the breakage of weak locations to form the apertures, which eventually results in the appearance of ZnO microsphere with small pores and big apertures.

Abstract: Based on the warm tension test and metallurgical microstructure observations, the change of the microstructure of B340/590DP dual-phase steel, especially the change of grain size in different strain rates and temperatures, was studied in this paper. The results of the experiment show that: in the warm tension tests of the dual-phase steel, both the dynamic recovery and dynamic recrystallization affect the grain size, and the influence of dynamic recrystallization is stronger. In different rates of extension, the microstructure all has the minimum grain sizes in the medium term of the dynamic recrystallization. In the medium term of the dynamic recrystallization under different rates of extension, the minimum grain sizes increase as strain rate drops. The temperature in which the minimum grain size forms decreases as strain rates drops.

Abstract: The WC and high-Cr cast iron layer were obtained on the surface of ZG30 steel by infiltration casting process, so the surface alloying of ZG30 steel was realized. The microstructures and phase structures of penetrating layer were studied by SEM, TEM, XRD, the hardness of the test material was measured by the hardness tester, and the wear resistance was tested by wear test machine. The mechanism of alloyed layer forming was analyzed. The effects of WC contents on the wear resistance of alloyed layer were studied. The results show that the layer is dense, without pores, slag and other defects, the thickness of the alloyed layer is about 6-7mm, and the penetrating layer and matrix are metallurgical bonding. The maximum hardness of the alloyed layer surface is 820Hv. When the content of WC is 15%, the penetrating layer has the highest wear resistance which is 18.8 times as high as the matrix.

Abstract: In this work, the electroless plating Ni-Cu-P on aluminium is obtained successfully by direct Ni-Cu-P plating method. The effect of bath compositions on the electroless plating rate and the properties of the electroless Ni-Cu-P deposits was studied by orthogonal test. The corrosion resistance, hardness, surface morphology and components of the coating were studied by using electrochemical workstation, digital micro-hardness SEM and EDS. The optimum bath formula obtained is 0.6g/L copper sulfate, 30g/L nickel sulfate, 35g/L sodium citrate, 25 g/L sodium hypophosphite, 20g/L acetic anhydride and right amount of self-made additive. The deposition rate, hardness and corrosion resistance are all good. The adhesion between the deposits and the matrix is better. The deposits is smooth and uniformity, smooth by SEM. The deposit contains Ni 78.90%, Cu 8.65%, P 12.46% by the analyses of energy disperse X-ray.

Abstract: Simulations are performed on atom substitution character in Ni-Al-V alloy based on microscopic phase-field model at 1046K. It was showed that the ordering of both Al and V atoms take place simultaneously during the precipitation process of Ni-Al-V alloy, V atoms substitute the Al sublattice in L1₂ phases, and they prefer β-sites to α-sites. Both of Al and V occupy the β-sites and complex phases Ni₃(Al_1-xV_x)are formed; V atoms substitute the Al sublattice, the D0₂₂ phases are formed at the boundary of L1₂ phases.

Abstract: This paper examines CuIn(Se,S)₂ (CISS) films prepared by sputtering precursor films of In, Cu, and In₂S₃ onto Mo coated soda-lime glass, followed by a single-stage selenium annealing process to form a CISS chalcopyrite phase. In this study, S was substituted for Ga to increase the energy gap of CuInSe-based materials. Experimental results reveal that the composition of (S + Se) and S decreased slightly with an increase in the selenium annealing temperature, exhibiting uniform distribution throughout the entire CISS film sample. The resulting CISS film exhibited p-type conductivity with an energy gap of 1.11eV. The optimum selenium annealing condition for the CIGS precursor prepared by sputtering was 798 K for 20 minutes.