Advanced Materials Research Vols. 488-489

Abstract: Ecological concrete has been playing an improving important role in normal life. Ecological concrete is a kind of concrete, with greater porosities, which can be used in public road, river bank engineering and so on. In this work, we proposed a way of researching ecological planning of river used Ecological concrete.

Abstract: In the present era, competition gets tougher; there is more pressure on manufacturing sectors to improve quality and customer satisfaction while decreasing cost and increasing productivity. These can be achieved by using modern quality management systems and process improvement techniques to reduce the process variability and driven waste within manufacturing process using effective application of statistical tools. Taguchi technique is well known technique to solve industrial problems. This technique is fast and can pinpoint the chief causes and variations. Plastic injection molding is suitable for mass production articles since complex geometries can be obtained in a single production step. The difficulty in setting optimal process conditions may cause defects in parts, such as shrinkage and warpage. In this paper, optimal injection molding conditions for minimum shrinkage were determined by the Taguchi design of experiment (DOE) approach. Polypropylene (PP) was injected in circular shaped specimens under various processing parameters: melt temperature, injection pressure, packing pressure and packing time. S/N ratios were utilized for determining the optimal set of parameters. According to the results, 2400 C of melt temperature, 75 MPa of injection pressure, 50 MPa of packing pressure and 15 sec. of packing time gave minimum shrinkage of 0.951% for PP. Statically the most significant parameter was melt temperature for the PP. Injection pressure had the least effect on the shrinkage. The defect rate was reduced from 14% to 3%.

Abstract: Global sustainability issues have led Malaysia, amongst other concerned countries to develop strategies on hazardous materials identification for construction industries. However, very few published literatures are found on the effects of building materials to social health, the environment and economy in building adaptation projects. There is a promising future for better building adaptation materials management but the issues and challenges highlighted require further actions for a positive difference. Encouraging usage of greener building materials and more research could be the way forward.

Abstract: In the present work, a centrifugal atomization was studied for producing zinc metal powder. The effect of rotating disc speed on median particle size, particle size distribution and standard deviation, production yield, and morphology of the atomized zinc powder was investigated. The atomization was carried out using graphite flat disc, melt pouring temperature, preheating disc temperature and melt feed rate of 40 mm, 550 °C, 300 °C and 50 kg/h, respectively. The atomizer disc speeds were varied from 10,000 to 30,000 rpm. It was evidenced from the experimental results that the median particle size and standard deviation of zinc metal powder decreased with increasing disc speed. The production yield tended to increase with increasing rotating speed. SEM images revealed that most zinc metal particles were irregular, elongated flakes. This kind of zinc power may be suitable for use as a friction material for manufacturing brake pad component in the automotive part industry

Abstract: Superconducting compounds (RE) Ba₂Cu₃O_7-x (RE = rare earth such as Y, Er, Sm and Nd) can be exploited in various industrial applications such as cables, electric motors and energy storage systems. The project aimed at synthesizing fine-particle YBa₂Cu₃O_7-x, ErBa₂Cu₃O_7-x, SmBa₂Cu₃O_7-x and NdBa₂Cu₃O_7-x, powders with compositions suitable for the applications. Solution combustion technique was employed in the synthesis, using urea as fuel. Compositional analysis obtained from x-ray diffraction indicated that the as-synthesized powders contained the desired (RE)Ba₂Cu₃O_7-x (RE123) superconducting phase and impurities, including (RE)₂BaCuO₅ (RE211), BaCO₃ and Ba(NO₃)₂. However, majority of the impurities were eliminated when the powders were calcined at 900°C. Only (RE)Ba₂Cu₃O_7-x (RE123) and (RE)₂BaCuO₅ (RE211) phases remained after calcination. Results from scanning electron microscope showed that the as-synthesized powders obtained from the solution combustion technique had relatively small particles with average particle size of 0.67 micrometers, while the calcined powders exhibited coarsening effects with average particle size of 4.4 micrometers.

Abstract: Bulk crystallization of B₂O₃-SiO₂-Al₂O₃-BaO-MgO glass system was investigated. Controlled heat treatment process was carried out between 900 and 1200°C to form glass-ceramics. Phase evolution in the crystallized glasses was studied by X-ray diffraction. Microstructures of the chemically etched surfaces were revealed by scanning electron microscope and micro-hardness was measured by Vickers hardness tester. High aspect ratio of aluminium borate whiskers were in the nano to micro regime and dispersed within the residual glass matrix. Whiskers had different sizes and compositions depending on the heat treatment temperature, which affected the surface hardness of the glass-ceramics. In general, increasing heat treatment temperature led to an increase in crystal size and length as well as the surface hardness (4.8 to 5.5 GPa). The whisker crystals oriented uniformly within the residual glass matrix leading to interlocking microstructure. The synthesized glass-ceramics in this study can be applied as machinable materials in various industries because their microstructures can resist microcracking and hence increase fracture toughness.

Abstract: The current work investigates anisotropy and forming characteristics of ZE10 Mg alloy. Anisotropic effects are measured by analysing tensile tests data for the specimens from 0o, 45o and 90o rolling directions of thin sheet of 0.8 mm thickness. The effects of temperature and strain rates are also included in anisotropic analyses. The mechanical properties of ZE10 alloy are affected by the physical conditions like temperature and strain rates. The effect is significant on yield strength, UTS and fracture strain while small variation is observed in case of Young’s modulus. Deep drawing experiments have been done to investigate the effects of temperature on forming characteristics and limit drawing ratio (LDR) of an alloy. Forming investigation shows that it is difficult to produce a good or unfractured part at 100 oC, but it can be produce at 150 oC or higher with different combinations of blank holder force and drawing ratio. Also, LDR and blank holder force also effects required punch force.

Abstract: The in-situ self propagating high temperature synthesis technique were used to synthesis tungsten based intermetallic alloys from WO₃/SiO₂/Al and WO₃/B₂O₃/Al reactant mixture system. The reaction was carries out in a SHS reactor under static argon gas at the pressure of 0.5 MPa. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The microstructure and phase distribution of the SHS reaction products were characterized by scanning electron microscopy (SEM) and energy dispersive x-ray (EDX), respectively. The results indicate that complete reaction of precursors to yield Al2O3-WSi2 and Al2O3-WB as product composites with clearly separation between Al2O3 and WB.

Abstract: The Fe₃Al-TiB₂-Al₂O₃ composite has been prepared by self-propagating high-temperature synthesis (SHS) from FeTiO₃-B₂O₃-Al system. The standard Gibbs energy minimization method was used to calculate the equilibrium compositions of the reacting species. The reactions were carried out in a SHS reactor under static argon gas at the pressure of 0.5 MPa. The effects of Al molar ratio of 4, 4.33 and 5 mole on the results product were investigated. The composition and microstructure of SHS products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The optimum result of Fe3Al intermetallics phase was obtained when using 4.33 mole of Al.

Abstract: The Perovskite Pb(Zr_0.52Ti_0.48)O₃ (PZT) ceramic powders were synthesized by sol-gel assisted process by using citric acid (CA), EDTA and Triethanolamine (TEA) as chelating agents. The phase evolution of the synthesized powders was investigated by powder X-ray diffraction (XRD) analysis. TEA assisted process yielded phase pure PZT powders at a relatively low temperature of 600 °C compared to CA and EDTA assisted process. Further, the phase purity of the powders were improved by sintering temperature of 800°C. Vibrational analysis of Metal-Oxygen bonding was carried out using Fourier transform infrared spectroscopic (FTIR) analysis. Showed a broad band in the spectrums between 500 cm^-1 to 700 cm^-1 attributed to the vibrations (Ti/Zr)O₆ and Ti/Zr-O from PbZrTiO₃. The morphology of the prepared powders was visualized using Scanning electron microscope. From the leakage current characteristics, EDTA assisted powder has higher leakage current densities compared to the CA and TEA assisted powders.