Applied Mechanics and Materials Vols. 423-426

Abstract: By applying new warm compaction forming technology of wood power developed through material forming theories in some interdisciplines such as applied science of wood and powder metallurgy, cotton stalk powder (CSP) was used as base material to prepare CSP/Al composite material of which the modulus of rupture and internal bond strength could be up to 83.95MPa and 6.82MPa respectively, wear resistance was 0.05g/100r and water absorption 0.65%. The sliding bearings made of the composite materials had a crushing strength and an apparent hardness up to 91.22MPa and HB51.1 separately. They are expected to replace sintered bronze of powder metallurgy in producing sliding bearings for light textile machinery so as to reduce the usage of nonferrous metal. The application of CSP/Al composite material explores a new way to use wood residuum in agriculture and forestry and ensure its high quality and cleanness.

Abstract: We chose a purging plug with good performance to analyze its insert plate. By X ray fluorescence analysis method, the main chemical composition is alumina and the small amount is silica. XRD analysis shows its phase compositions, main crystal phase is corundum, the secondary phase is mullite. SEM analysis is for the microstructure, grains are packed closely. They are sintered tabular corundums with smooth shape, which means there is liquid phase in sintering process to help mass transfer. As a conclusion, this product is designed from the point of material selection and structure control to improve its thermal shock resistance. Compacted microstructure combining with good thermal shock-resistance mineral phases improve the service life of purging plug.

Abstract: In this study, silvergrass (SV) reinforced high density polyethylene (HDPE) composites (WPCs) were prepared by injection molding. The effects of maleated polyethylene (MAPE), slivergrass fibers content on the mechanical, Differential scanning calorimeter, morphologies of WPCs were investigated. It was found that the mechanical properties of the SV reinforced HDPE composites can be improved by MAPE treatment. The highest tensile strength and flexural strength of the composites can be reached with 40% and 50% SV contents at the fixed 8% MAPE respectively. The SV can be the nucleating agent with the addition of MAPE. SEM images of tensile fracture surfaces of treated composites demonstrated better fiber-matrix adhesion.

Abstract: In order to investigate the anti-crush properties and the corresponding deformation mechanism of hollow integrated woven textile sandwich composites (IWTSCs), the quasi-static out-of-plane compression experiments are carried out. A set of typical deformation curves with a relative stable deformation plateau are obtained. The coupled compression-shear deformation and the ductile failure mechanism of IWTSC is discussed. Combining with qualitative analysis, comparisons between three kinds of IWTSC panels with piles of different density and thickness reveal the key to design a ductile IWTSC.

Abstract: A FeAl/WC nanocomposite coating was produced by cold spraying of mechanically alloyed Fe/Al/WC composite powder assisted with annealing treatment. The microstructure and grain size of FeAl/WC nanocomposite coating before and after annealing treatment were characterized. The results indicated that as-sprayed Fe (Al)/WC nanocomposite coating presented a dense microstructure with lamellar structure. The phase transformation from Fe (Al) solid solution to FeAl intermetallics within as-sprayed nanocomposite coating occurred when annealed at 550°C for 25 h. The annealed nanocomposite coating was composed of nanograins of size ranging from 50-100 nm and the grain size of FeAl increased with increasing the annealing time. Moreover, the effect of annealing temperature on the microstructure of the FeAl/WC nanocomposite coating was investigated.

Abstract: TiO₂/tourmaline composite photocatalyst materials were fabricated mainly by the sol-gel technique. Study found that, TiO₂/tourmaline composite photocatalyst materials, under the bombardment by electron beam in SEM, would turn to be brighter and attract each other, and the electrostatic gravitation among the TiO₂/tourmaline composite photocatalyst materials granules grow up evidently on their surfaces with the accumulations of electron from the electron probe, so as to be strong enough to force the TiO2/tourmaline composite photocatalyst materials granules to be shifted rapidly and accumulated into clusters ultimately, and the granules which were heat treatment on 600°C for 3h shifted most strongly. And the average absorption rate of TiO₂/tourmaline composite photocatalyst material was stronger than nano-TiO₂, in the visible region of wavelength 400-500nm. In addition, TiO₂/tourmaline composite photocatalyst materials were capable of activating water molecules to reduce agglomeration of water molecules, and to increase the amount of dissolved oxygen in the Photocatalytic reaction system.

Abstract: Merits of lightness and high strength of composite holding pole are introduced in this paper; in addition, three structures are calculated and compared with traditional holding pole made of aluminum alloy so as to prove the former can replace the latter.

Abstract: A honeycomb core sandwich panel is superior in impact absorption under whole surface compression, because of the buffer effect of core. However impact properties of honeycomb sandwich panels under local compressions such as drop weight impact are affected by the plates as the face sheets in addition to the core layers. This research describes the drop weight impact properties of honeycomb sandwich panels which consist of various aluminum-alloy honeycomb cores and CFRP composite laminate faces through the spindle falling experiments. In order to confirm the validity of the experiments convictively, analytical approaches based on 3D modeling and ANSYS LS-DYNA software were also carried out. Comparisons of the experimental and analytical results are reported in this study.

Abstract: In this study, silvergrass (SV) reinforced high density polyethylene (HDPE) composites were prepared. The effects of polymeric methylene diphenyl diisocyanate (PMDI), slivergrass fibers (SV) content on the thermal, crystalline properties of wood plastic composites (WPCs) were investigated. It was found that Compared with the untreated WPCs, the thermal stability of the composites after incorporation of PMDI treated SV fibers was significantly improved. Moreover, the results show that with PMDI treated composites, SV was an effective heterogeneous nucleating agent.

Abstract: The conductivity of amorphous AlSiCN ceramics derived from polymer pyrolysis were investigated under applying stress. A huge gauge factor was observed, just as that of SiCN ceramics with a proper thermal initiator, and their piezoresistivity are a strong sensitive to stress applied. The high piezoresistivity effect and sensitivity to stress are due to compositional and mechanical properties of polymer derived AlSiCN ceramics.