Advanced Materials Research Vols. 311-313

Abstract: In this paper, the surface tension components of three silicone resins were determined with an advanced contact angle technique, which was composed of dynamic cycling contact angle and axisymmetric drop shape analysis (ADSA). The interfacial properties of three silicone/quartz glass fiber composites were measured through interfacial shear strength (IFSS) testing experiment. It was found that the Lifshitz–van der Waals component was the main surface tension component for all of the silicones. There is a perfect linear relationship between the interfacial tension and the IFSS. With the increase of the Lifshitz-van der Waals component, the interfacial tension and the IFSS of composites increased. Therefore, the Lifshitz-van der Waals component is the most important parameter for explaining the interfacial shear property of silicone/glass fiber composites.

Abstract: The surface of wood/polyethylene (PE) composites were treated by mechanical polishing treatment and coating treatment, and the structure of surface for wood/PE composites before and after treatment was characterized by fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) in this paper. Combined with bonding strength test, the effect of coupling agent KH-560 (2,3-epoxypropoxypropyltrimethoxysilicane) on bonding properties of wood/PE composites was also investigated. The results showed that, the -OH, -C-O- and C=O functional groups were appeared on the treated surface and the surface roughness increased after mechanical polishing treatment and coating treatment, which increased the shear bonding strength for the treated sample significantly. And the coupling agent KH-560 can increase the bonding strength for the composite more significantly due to the co-reaction of epoxy groups which introduced by coupling agent with epoxy resin adhesives.

Abstract: MMCs can be usually fabricated by powder metallurgy, stir casting and spray co-deposition, etc. Al₂O₃/Al composites were produced by means of reciprocating extrusion with alumina and pure aluminum particulates in the present study. The microstructure was analyzed by scanning electronic microscope, and the mechanical properties were measured by hardness tester and universal testing machine, respectively. The results showed that Al₂O₃/Al composites with as high as 20 vol.% alumina can be successfully produced by reciprocating extrusion. During reciprocating extrusion process, the reinforced alumina particles can be fragmentized and uniformly distributed in the aluminum matrix. The tensile strength and hardness of the composites increase as volume fraction of alumina particles increases, whereas the elongation decreases. Compared with the pure aluminum compact, the tensile strength and hardness of the composite with 20 vol.% alumina particles is 29.3% and 93.5% higher, respectively; whereas the elongation decreases 66.6%, and the fracture mechanism of the composites is attributed to ductile rupture.

Abstract: An experimental campaign on metallic-palm fiber-metallic hybrid subjected to impact loading using spherical projectile has been carried out. High initial energy impact with projectile mass of 24 kg and speed of 1, 3 and 5 mm/s, has been set enabling to determine the energy absorption capability of hybrid composite panel. The influence of stacking sequences metallic-palm-fiber-metallic and metallic-palm fiber-metallic-palm fiber-metallic with different thickness of metallic and palm fiber, to the energy absorption were investigated. The effect of different striker radius; 10, 13 and 20 mm were carried out as well. The mechanism of failure and energy absorbed by the hybrid composite panel and its components; metallic alone and palm fiber alone, were carried out to understand the advantage of having hybrid structure. The optimum configuration of hybrid panel in term of stacking sequence to absorb the energy of impact is proposed. The methodology of this study can be used for designing the armor to absorb the energy of projectile using palm fiber composite panel.

Abstract: In this study, wood plastic composites (WPC) material were fabricated with wood flour and polyvinyl chloride (PVC). To improve the interfacial compatibility between the wood flour and the PVC, silane method (SM) and tianate method(TM) were used to treat the wood flour, maleic anhydride copolymerized PVC with dicumyl peroxide. The effects of wood flour content, surface treatment on the mechanical properties of WPC materials were investigated. Fracture surfaces of tests specimens were analysis by SEM. Test results indicate that WPC material with wood flour treated by SM or TM together with PVC copolymerized showed good mechanical properties.

Abstract: Carbon-encapsulated NiO (NiO@C) sphere-like composites were synthesized at 170 °C for 12h by a one-pot hydrothermal approach. Ni(Ac)₂•4H₂O, sucrose, and PEG-400, were selected as a precursor materials. X-ray diffraction analysis (XRD) and scanning electron microscopy image show the products of NiO@C sphere-like composites by the present process. Microwave-absorbing measurement shows the NiO@C composites exhibit good microwave absorbing property. The reflection loss (RL) values of the products are lower than −10 dB in the frequency range of 2–18 GHz with value as low as −40 dB at 2 GHz.

Abstract: Multi-walled carbon nanotube (MWCNT) reinforced aluminum (Al) nanocomposites were synthesized using powder metallurgy technique followed by hot extrusion. 0-3wt.% MWCNTs were incorporated. Simultaneous improvements in density, harness and tensile strength were obtained with the incorporation of MWCNTs in the Al matrix. An enhancement in tensile strength as high as 120% was obtained in the Al-2.0MWCNT compared to monolithic Al. A comparison was made between the experimental tensile strengths of the nanocomposites and the predicted ones determined by Kelly-Tyson model. It is found that declined value of the experimental result at higher MWCNT content (above 2wt.%), attributed to the clustering of the MWCNTs at higher addition.

Abstract: The present research work concerns the development of TiC reinforced 316L stainless steel composites through powder metallurgical technology and sintered in vacuum. The effect of TiC particle addition and cooling rate on the mechanical properties of 316L stainless steel composites has been investigated. The results show that increasing the cooling rate caused enhancement of ultimate tensile strength and microhardness. However, the elongation to failure of the composites was decreased with the increase of cooling rate. The addition of TiC particle was found to improve the ultimate tensile strength of 316L stainless steel composites. The highest tensile strength was 648 MPa in specimens containing 5wt.% TiC. Further increase in TiC content to 10wt% results in a reduction in tensile strength to 631 MPa.

Abstract: Magnesium matrix composites reinforced by SiC particles of different size have been fabricated by vacuum pressure infiltration to investigate the influence of volume fraction and particle size on wear properties. It was found that the wear resistance of SiC_p/Mg composites increased as volume fraction of particles with the same average diameter and reduced with the decrease of average diameter of particle, whereas the grooves furrow and adhesion increase. The influence of particle diameters on wear resistance was more prominent than that of volume fraction. The wear mechanism of composite and matrix alloy were oxidation, adhesive and delamination wear.

Abstract: Polypropylene/organo-montmorillonite (PP/OMMT) composites were investigated by XRD. Friction and wear behaviors of this composites sliding against GCr15 stainless steel were examined on M-2000 text rig in a ring-on-block configuration. Worn surfaces of PP and its composites were analyzed by SEM. The result shows that PP macromolecule chains have intercalated into OMMT layers and form intercalated nanocomposites. With the increase of mass fraction of OMMT, both wear rate and friction coefficient of composites first decrease then rise. With the increase of load, from 150 N, 200 N to 250 N, wear rate of composites increases, while friction coefficient reduces. The wear mechanisms of composites are connected with the content of OMMT. Composites were dominated by adhesive wear, abrasive wear and adhesive wear accompanied by abrasive wear respectively with the increase of OMMT content.