Advanced Materials Research Vols. 712-715

Abstract: Monel K-500 alloy is an important nickel-based corrosion resistant material with excellent corrosion resistant ability in various corrosion circumstances (include electrochemical and chemical corrosion) and good mechanical properties. However, Monel K-500 alloy is also a sensitive material to high temperature. Hot working process has significant effect on its working character and quality. In view of existing problems in domestic manufacturing enterprises, some experiments were carried out in different working temperature, deformation degree and strain rate to investigate the performance of Monel K-500 alloy in hot working process. The research results show that moderate temperature, higher strain rate and deformation degree will be favorable to improve crystal structure and mechanical property of Monel K-500 Alloy.

Abstract: In this article, the authors use of Si, Mn, Cr as the main alloying element, developed a tough wear resistant cast 35CrMnSiMo, after casting, to obtain a wear-resistant cast steel with a hardness and impact toughness mechanical performance testing, metallurgical microscope and scanning electron microscope analysis of the microstructure. The results show that, the cast 35CrMnSiMo 850 °C austenitizing insulation 30min and then quenched, the material water hardened degrees is much larger than the oil hardened degrees. The the water hardened than oil hardened degrees up 28.5%. Metallographic photo clearly see a lot of lath martensite, the small amount of lath martensite and retained austenite, the oil quenching microstructure edge outline is somewhat vague, while clear the water quenching microstructure edge contour darker, impact toughness with hardness is inversely proportional to the sample.

Abstract: This paper mainly through the experimental study on the heat treatment process and mechanical properties of cast steel 35CrMnSiMo.According to the effect of alloy elements in design of a high-toughness abrasion-resistant cast steel, Cr, Mn, Si, as the main alloy elements, supplemented by a small amount of Mo, the casting molding, for hardness and impact toughness test of mechanical properties of experimental steel. The results show that, the as-cast 35CrMnSiMo by 880 °C, quenching for 20min then, the same quenching temperature, quenching hardness of materials is far greater than the oil quenching hardness. Water quenching hardness up to 25% higher than the oil quenching hardness, The impact toughness of specimen is inversely proportional to the contrast relationship Hardness.

Abstract: With butyl stearate (BS) as the core material and melamine-formaldehyde resin (MF) as the wall material, BS-MF resin microcapsules were synthesized under in situ polymerization method. The microcapsules were characterized using FTIR, SEM and other methods. The four-ball friction method was performed to test the tribological property of the microcapsules when polyethylene glycol was taken as the base fluid. The results showed that base fluid with 3% microcapsules had a friction coefficient as small as 0.053 and the wear scar diameter could be 0.326mm (4%) under 314N. The microcapsules were ruptured under the action of friction and then the reactive group formed physical adsorption film. The physical adsorption film, together with the subsequently formed friction polyester film, presented a synergistic lubricating effect.

Abstract: Surface modified nanocrystalline cellulose (NCC) was prepared by silicon-69, and then blended into natural rubber latex to prepare nanocomposites. The nanocomposites properties of tensile properties, tear strength, morphology and thermal dynamic mechanical properties were measured by mechanical property testing, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA), respectively. The results showed that modified NCC is homogeneously distributed throughout NR matrix, which leads to the enhancement on mechanical properties. Moreover, the storage modulus (E) of modified nanocellulose filled NR is higher than unmodified nanocellulose filled NR, and the tanδ is reversed.

Abstract: The isothermal oxidation of the ZrB₂-SiC-ZrC ceramic was carried out in static air at a constant temperature of 1500±15 oC for 20 min. Compared with the original strength of 580 MPa, the strength of the oxidized specimen increased to 655±45 MPa, because the flaws in the surface of the specimen were sealed by the oxide layer. The thermal shock resistance of the specimens before and after the oxidation was measured by the water quenching. The measured ΔT_crit for the oxidized specimen was 641 oC that was obviously greater than 348 °C for the unoxidized specimen. The improvement in the thermal shock resistance was attributed to the formation the oxide layer on the surface of the specimen. The results here pointed to a promising method for improving strength and thermal shock resistance of ZrB₂-based ceramics.

Abstract: Pyrolysis of vulcanized rubber (VR) with high total sulfur was carried out in the fixed-bed reactor. The effect of heating temperature and on the formation and distrubtion of tar, gas and char and sulfide in pyrolysis products were investigated.The maximal tar yield can reach 55.79% (wt,dry), water yield 1.30% (wt,dry). With increase in temperature, sulfur in char decreases and more sulfur migrates into gases and sulfur removal varies from 66.08% to 77.39 %, and the contents of H₂S, CS₂ and COS increase. Comparing with COS and CS₂ , the content of H₂S is overwhelming, since sulfur radicals from crack of VR is easier for hydrogenation reaction to produce H₂S. GC-FPD (Flame Photometric Detector) was used to determine the sulfides in tar. The result indicates sulfides in tar are mainly present in form of sulfides with aromatic group. When temperature grows, sulfur transfers into pyrolysis gas instead of char and total content of detected sulfides in tar rises and then declines.

Abstract: Ethyl cellulose based acrylate (AEC), an ethyl cellulose based macromonomer, was successfully synthesized by the esterificaiton reaction between ethyl cellulose and acryloyl chloride in homogeneous media and characterized by FTIR, ¹H NMR, ¹³C NMR, differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The results showed that acrylic group was facilely grafted onto the backbone of ethyl cellulose. In addition, AEC was proved to be able to homopolymerize and copolymerize with other monomers such as butyl acrylate in the presence of free radical polymerization initiator. We believed that development of AEC together with the analysis of its structure and properties would contribute to further utilization of cellulose based materials.

Abstract: Lead zirconate titanate (PZT) ceramic as a kind of widely used piezoelectric material is developing very fast for these years because of its high piezoelectric properties. Therefore, various theories have been developed for describing the mechanism of the degradation process of the PZT ceramic [1-4]. However, there are still many contentions in these reported theories. In this paper, experiments on commercially available lead zirconate titanate (PZT) ceramic samples have been designed. Through this work, it has been found that the leakage current is increasing with the electrical degradation process of the PZT ceramic. Self-recovery and re-degradation phenomena and formation of black spots have also been observed. It has suggested that the duration of the re-degradation process depends on the duration of the self-recovery and the re-degradation process would not produce any black spots and the black spots are only formed during electrical degradation process.

Abstract: Traditional RTM process were difficult to integrally manufactured Composite components with complicated internal structures because the metal molds are heavy and expensive. LRTM process and Water-soluble core-mould materials could be used to solve the problem due to their flexibility, mechanical properties and water solubility. In this paper, manufacturing process and properties of water-soluble core-materials were studied. Moreover, using Light Resin Transfer Molding (LRTM) process to manufacture a hollow-structure, made of carbon fiber reinforced polymer.