Materials Science Forum Vol. 889

Abstract: Aluminium composites are widely used in a variety of applications including aerospace, automotive, defence, thermal as well as in sports and avocation. Technological and industrial demands often account to inculcating special properties to materials to achieve its target that may not be achieved by conventional materials. This phenomenon was widely observed in the recent decades in fields of aerospace and transport where high performance materials with low densities are required. The primary objective of this work is to develop an Aluminium Metal Matrix Composite (AMMC) by in-situ stir casting for naval applications and successfully bring about self-lubrication properties, thereby lowering wear rate and improving corrosion resistance. This is done by adding graphite at various weight fractions to the base metal. The fabricated composites are subjected to various mechanical tests and corrosion test. It was found that ,increase in graphite addition improves the Microhardness of the material, improves the wear resistance and enhances its corrosion resistance. The materials were further observed and found that , there will be lower tensile strengths compared to the base metal with increase in addition of graphite particles.

Abstract: Silicon and Silicon Nitride are vigorously utilized and explored in micro and nano fabrication technology as they have excellent mechanical and electrical characteristics suitable for NEMS device application. In this study, both of them are analyzed using COMSOL Multiphysics software to evaluate the strength capability of the material when used as filtration membrane in artificial kidney. The artificial filtration membrane is a crucial part in an artificial kidney system as it functions to filter out all wastes from blood stream. This paper investigates the effect of membrane thickness experiencing applied pressure of 1332.3 Pa and 7332.7 Pa on membrane deflection and von Mises stress at the center of the filtration membrane. Those mechanical characteristics at different pore geometry and structure are evaluated against applied pressure on the filtration membrane surface. The results show that the pore geometry and shape for a membrane with thickness of higher than 200 nm will not have significant influences on the deflection and stress characteristics. Therefore, thicker membrane will result to a more stable filtration process that would be able to withstand simulated blood stream pressure in an artificial kidney.

Abstract: Bacterial cellulose (BC) is the cellulose which is produced by specific bacteria such as Acetobacter xylinum, Agrobacterium, Gluconacetobacter, Rhizobium, Achromobacter, Alcaligenes, Aerobacter, Azotobacter, Salmonella, Esherichia, and Sarcina. Surface modification of bacterial cellulose (BC) by coating with synthetic biodegradable polyester on it was reported. BC films were coated with the polymer at different concentrations in order to improve the surface structure of BC. Tear and burst indices of the BC film were increased with such modification.

Abstract: Halloysite nanotubes (HNT) are good reinforcing fillers because of many traits that allow high processability and versatile active agents loading. Incorporation of HNT into polymer matrices, especially in natural polymers, is still yet to be explored. This paper reports on the effect of inclusion of nanotube clay towards the mechanical properties of polysaccharide films.

Abstract: The dental restorations by the usage of implants have been one of the most favourable treatment. However, the existing dense dental implant causes overloading towards the human bone that triggers ‘stress shielding effect’ and also implant loosening. This paper focused on the development of highly porous Ti-6Al-4V dental implant by metal injection molding with palm stearin binder system with an addition of sodium chloride as space holder which has been established in the fabrication of porous Ti-6Al-4V. The evaluated compositions consist of the powder volume fraction of 63vol% and 65vol%. SEM analysis shows that highly porous Ti-6Al-4V dental implant were obtained. The average density is 3.325g/cm³ for 63vol% sample and 3.915g/cm³ for 65vol% sample. While for the Vickers hardness are 113.68HV and 162.8HV for 63vol% and 65vol% respectively.

Abstract: In high speed machining, to dynamically control the mechanical behaviour of the materials, it is essential to control temperature, stress and strain by appropriate speed, feed and depth of cut. In the present work, to predict the mechanical behaviour of Ti6Al4V and 316L steel bio-materials an explicit dynamic analysis with different cutting speeds was carried out. Orthogonal cutting of 316L steel and Ti6Al4V materials with 720 m/min, 900 m/min and 1200 m/min cutting speeds was performed, and the distribution of stress and temperature was investigated using Jonson-Cook material model. Additionally, the work aimed at determining the effect of cutting speed on work piece temperature, when cutting is carried out continuously. From the investigation, it was found that, while machining Ti6Al4V material, for the increase in cutting speed there was increase in tool-chip interface temperature. Specifically, this could found till the cutting speed 900 m/min. But, there was a decrease in tool-chip interface temperature for the increase in speed from 900 m/min to 1200 m/min. Similarly for 316L steel, the tool-chip interface temperature increased when increasing the cutting speed till 900 m/min. But reduction in temperature from 650 °C to 500 °C for steel and 1028 °C to 990 °C for Ti6Al4V were found, when the cutting speed increased from 900 m/min to 1200 m/min. The study can be used to conclude, at what temperature range the adoption of material with controlled shape and geometry is possible for potential applications like, prosthetic design and surgical instruments prior to fabrications.

Abstract: Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) test were utilized to detect the phase transformation of a HA/Ti Functionally Graded Material (FGM) prepared via Powder Metallurgy (PM) technique. The effects of oxygen (O₂), nitrogen (N₂), forming (N₂+H₂) and Argon (Ar) sintering atmospheres on the FGM specimens were examined by considering the gas flowing duration. It was found that the original metallurgical profile of pure Ti in HA/Ti FGM sintered under N₂ atmosphere was almost preserved. However the carburization of the pure Ti was observed on the specimen. Medium alkyl halides (C-Br) and alkenes (-C=C-) stretches were detected, producing the dominant elements in the pure Ti layer of the specimen. The almost stable constituent element remains in the specimen sintered under flowing N₂+H₂ atmosphere as detected by XRD result. This proved the significance of controlling the sintering atmosphere during the entire sintering process. The results achieved reveal the high tendency of Ti and HA elements to react with the sintering environment, thus very precise furnace with controllable atmosphere is crucial for the fabrication of the HA/Ti FGM.

Abstract: Gamelan is traditional musical instrument that evolves especially in Bali, its function is to accompany the religious and cultural ceremonies of Hindus. The making process of gamelan, smelting bronze alloys, is done by using traditional furnaces. The use of charcoal as fuel in smelting process causes melting furnace performance is difficult to determine. That condition impacts the effectiveness of the smelting process especially in determining the needs of fuel and the processing time. Therefore, it influences the productivity of crafters. This research was conducted to test the performance of the furnace in accordance with a design that is commonly used by artisans. The observation was done at the temperature of melting, melting time, data retrieval was conducted repeatedly three times on different days. Based on the analysis and observation in accordance with the experimental design made whereby in the smelting process to achieve the casting temperature indicated as follows. The average temperature of smelting is 730,8 °C, fuel use is 23 kg, melting time is 39.76 minutes as well as the efficiency of the furnace 36.80%. Based on the analysis conducted, low efficiency is due to the surface of the furnace which is designed open, so that during the energy generated in the process of burning a lot of fuel wasted into the environment.

Abstract: Studies of the properties steels and alloys in the liquid and solidity conditions bear witness that the technical peculiarities of the receipt liquid metal in particular overheating have influence on the its properties and structure. The time-temperature treatment of the liquid metal influence on the structure of the liquid metal. The structure of the liquid metal influence on the character hardening and properties of the solidity samples in the one's turn. It should be noted the fact that place the just regularity take place: than extent of the melt equilibrium before crystallization is higher the solid metal distinguish oneself the better figures of the quality.

Abstract: There is a unit proposed for investigations in the high-temperature metallic liquid alloys, using image photometry of a “large melt drop” resting on the horizontal backplate. The unit is designed to determine the density d and surface tension σ of a sample of the mass given, placed into a horizontal electric furnace. Using a volumenometer enables measuring the geometric parameters of the drop. Various ways of expanding the range of operational functions are presented, in particular, extending the temperature range Δt^o and improving the unit efficiency as well as decreasing the artifacts’ impact. Updating the unit enables the studies (including the comparison studies) of both luminous and nonluminous samples to be conducted combining various ways of illuminating both the melt drop’s contours and surface. The ways of reducing the influence of vibrations and refining the backplate’s horizontal position as well as the possible measures for partial cleaning the films from the drop surface of the multicomponent melt are proposed. The use of the unit updated on the basis of approaches developed and patented by the authors enables reducing the time to be spent on measurements, expanding the range of the unit’s operational functions, decreasing the artifacts’ impact and improving the validity of the results obtained.