Advanced Materials Research Vol. 748

Abstract: Austempered Ductile Iron (ADI) is a type of nodular, ductile cast iron subjected to heat treatments - austenitising and austempering. Whilst machining is conducted prior to heat treatment and offers no significant difficulty, machining post heat treatment is demanding and often avoided. Phase transformation of retained austenite to martensite leading to poor machinability characteristics is a common problem experienced during machining. This case study explains the effect of feed rate on machinability of ADI using cutting force analysis and tool failure analysis. The experimental design consists of conducting drilling trials on grade 1200 and 1400 at constant depth of cut, 25mm; constant speed, 45m/min; no coolant and variable feed rates from 0.2 to 0.35 mm/rev (increment of 0.025mm/rev). Metallography and X-ray diffraction technique was carried out in order to identify and quantify the microstructural phases before and after drilling. The results from the trial infer that the best way to machine ADI efficiently without tool failure is using low feeds and high speeds and without coolant.

Abstract: In diamond wheel precision grinding process, the grinding force of nanoceramic coating materials can be divided into single grain grinding force and wheel unit area grinding force, this paper studied the two grinding force, results showed that, with the increase of grinding depth, grinding wheel per unit area grinding force and single grain grinding force increased. The two kinds of grinding force increased also with the increase of workpiece feeding speed, the normal grinding force and the tangential grinding force decreased with grinding wheel speed increase. grinding parameters, as diamond wheel grit size and binder type, effected also on the grinding force.

Abstract: Blow forming technology has been used to produce glass and plastic components with easy and simple process. In order to apply this technology to metallic system, relatively high formability of material and elevated temperature are required. Since the blow forming temperature is quite high for metallic system, the main difficulty is to obtain adequate mold material which can sustain pressure difference between inside and outside of the tool. The present study demonstrates blow forming process with IN718 and steel can be applied to manufacturing of combustion chamber in liquid propellant rocket engine with complex shape. The result shows that the developed technology to process design of high temperature blow forming by the finite element method can be applied for near net shape forming of a combustion chamber of liquid rocket engine and a cone-shaped chamber extension part with cooling channels.

Abstract: The mechanical properties and microstructure characteristics in nano-ceramic coating material determine largely their grindability, there are a variety of wear mechanisms existing in grinding process, wear resistance of nanoceramic coatings are higher than normal ceramic coating, processing zone in ceramic materials can be divided into inelastic deformation zone and elastic deformation zone. In the process of nanoceramic coatings materials removal, inelastic deformation removal and brittle removal is the coexistence, the grinding force, existing in nanostructured ceramic coatings, is bigger than it in general structure ceramic coating. In plastic deformation materials removal mode, the grinding surface roughness is low, while in brittle removal , surface grinding roughness is high , prone to grinding surface/subsurface damage.

Abstract: Milling is a machining process by which a surface is generated by a progressive chip removal. An experimental investigation has been carried out on the performance of up and down milling under dry and flood conditions when end milling medium carbon steel utilizing titanium coated carbide tools. The performances are evaluated in terms of the cutting force, specific energy and power of cutting tool. The results show that milling in dry condition under up milling mode produce higher cutting force, specific energy and power. However, cutting under down milling mode gives less significant effect either being cut in dry or flood condition.

Abstract: The objective of this research was to develop a new form of clad layer by producing a Silicon Carbide (SiC) particle reinforce Metal Matrix Composite (MMC) using the iron based alloys as the matrix material. A 1.2kW continuous wave CO₂ laser was used in this research. A gravity feed system was used with one powder feed which contained different percentages of SiC particles and iron based powder. Experimental results showed that the decomposition of SiC particles was observed and only a few SiC particles were found in the clad matrix. High micro hardness values were found in the SiC clad which were in excess of 1000 HV. However, most of the SiC were evaporated which created porosity in the melt pool. Therefore, blown powder technique is recommended for overcome this problem.

Abstract: In this Research, Taguchi optimization methodology is used to optimize Rotary Ultrasonic Machining (RUM) parameters for face milling of zirconia ceramic. The influence of the RUM parameters such as vibration frequency, vibration amplitude, spindle speed, feed rate, and depth of cut on cutting force and material removal rate (MRR) is studied. A three-level orthogonal array table is used to determine the signal-to-noise (S/N) ratios based on Taguchis design of experiments. Furthermore, analysis of variance (ANOVA) has been performed to study the relative significance of the different factors on cutting force and MRR of zirconia ceramic. Finally, verification tests were carried out to compare the predicted values of the outputs with their experimental values in order to confirm the effectiveness of the Taguchi Optimization.

Abstract: Green polymer foam was prepared by the reaction of green monomer based on vegetable oil with commercial Polymethane Polyphenyl Isocyanate (Modified Polymeric-MDI) and distilled water (H₂O). The morphological study of green polymer foam was examined by Scanning Electron Microscope (SEM) and acoustic property by means of H₂O composition ratio equivalent to weight of polyol. It was found that the cell size of green polymer foam has significantly increment as well as H₂O loading increased. Increasing of H₂O more than 50% equivalent to weight of polyol shows nonuniform pore distribution, large average pore size and smallest number of pore. Furthermore, the cell size of neat green polymer foam gives 400μm up to 1833.3μm with high loading of H₂O. In addition, the cell size of green polymer foam influences by the increasing amount of H₂O loading and enhanced the sound absorption property at low frequency level.

Abstract: Biodiesel is defines as monoalkyl fatty acid ester has represents a promising alternative to be substituted as an alternative fuel for the use of diesel engines and it is produced by chemically reacting the vegetable oil with an alcohol in a process called the transesterification process. The reaction usually requires a catalyst such as sodium hydroxide (NaOH) or potassium hydroxide (KOH) and methanol to obtain chemical compound called methyl esters which will then be known as biodiesel. The approach of this research is to enhance the yielding of Fatty Acid Methyl Esters, FAME by using ultrasound clamp on tubular reactor. With the assistance of the ultrasound clamp, immiscible liquids such as the vegetable oil and methanol will be able to emulsify together in a short period of time comparing to the conventional method which is by stirring the mixture leading to a longer period of time to emulsify and to achieve the desired yield of FAME. The use of ultrasonic energy will eventually cause the rapid movement of the mixture hence creating cavities where the liquids will breaks down and cavitation bubbles is produced. The optimum results for biodiesel production using ultrasound clamp assisted on the tubular reactor is 1 minute with the conversion of esters 94 % as compared to the previous researcher which achieve 98 % of esters conversion within 5 minutes. Higher esters conversion was achieved through the presence of methanol to oil molar ratio of 9:1 and 12:1, catalyst concentration of 0.75 Wt. % , 1.00 Wt. % and reaction temperature at 64 oC is being studied.

Abstract: The mechanical properties of a product made in Fused Deposition Modelling (FDM) rapid prototyping are strongly dependant on process parameters selected during part fabrication. Acrylonitrile butadiene styrene (ABS) is a common material used in FDM systems. The advantages of ABS include high strength and rigidity with toughness and these properties make it one of the most common thermoplastics used in engineering applications. This paper describes an experimental investigation of dynamic stressstrain response of ABS parts made by fused deposition modelling for three different part build orientations. Currently there is limited research available for this aspect of ABS material processed by FDM systems. The high strain rate compression tests were performed using a Split Hopkinson Pressure Bar apparatus to determine the dynamic stress-strain response and results were compared with quasi-static behaviour of the same specimens.