Advanced Materials Research Vol. 576

Abstract: This paper presents an alternative method to optimize parameters on single V butt welding. The effect of single-passed welding parameters such as current, voltage, welding speed and width of weaving movement on major welding defects by using a one-sided clamping method was investigated. The optimum parameter values were analyzed using Multi Objective Taguchi Methods (MTM) which started with the application of the common Taguchi methods (L8) Orthogonal Array (OA) and Total Normalized Quality Loss (TNQL) followed by ANOVA under simultaneous consideration of response weighting factors. Further, the value was analyzed by employing Multi Signal to Noise Ratio (MSNR). For the experimental study, a robotic welding system ABB IRB 2400/16 with digital welding power source KEMPPI Pro Evolution ProMIG 540 MXE with shielding gas Argon 80% and Carbon Dioxide 20% were applied. The material used is low carbon steel with 4 mm plate thickness. Based on the verification test result, it is found out that MTM can be used as an alternative method to investigate the optimum value of single passed welding parameter with multiple quality features.

Abstract: In this project, the residual stress due to multipassed welding process at the fillet weld will be studied using 2D Finite Element Analysis (FEA) simulation method and experimental investigation. Due to the extensive capabilities and dedicated tools for the simulation of welding, including material deposit via element activation or deactivation and predefined or customized moving heat sources, SYSWELD 2010 was chosen as the FEA software. The material with a thickness of 9 mm was structural steel S355J2G3 for simulation and low carbon steel for the experiment. The clamping condition was selected to obtain the best relationship between simulation and experiment by using Strain Gage. The model was dedicated to multipassed welding using the robotic welding system

Abstract: The cost of development of WPS will be very expensive if the welding parameter is selected based on trial and error. Optimal welding condition cannot be easily guessed unless the operator has records of good welding. If a calculator that can predict the welding parameter for the desired bead geometry accurately, such tool will be extremely useful for any fabrication industry. This paper intends to investigate the correlation between the welding parameter and weld bead geometry of 2F position T-fillet carbon steel, when welded by 1.2 mm diameter wire submerged arc welding. Keeping only one parameter as variable, 2F fillet weld coupons are welded by SAW with a range of welding current, welding voltage and welding speed. Only weld bead geometry that complied with the quality requirement of code of practice AWS D1.1 is considered. The trendline graph is created to fit the correlation between the heat input and the fillet weld geometry. By incorporating the trendline formulas into the calculator, the weld bead geometry can be predicted accurately for any welding parameter. The mean absolute deviation (MAD) between the predicted geometry and the experimental results is less than 0.50mm.

Abstract: In this paper, a local/global approach has been used to predict weld induced distortion in butt joint. This approach combines non-linear thermo-elastic plastic and linear elastic analyses to compute final distortion triggered by the welding process. Distortion can lead to dimensional inaccuracy and thus causing the rise in fabrication cost. In this study, Finite Element Method (FEM) software Sysweld and Pam-Assembly were used for computing the welding deformation. The material used for the simulation was low carbon steel with thickness of 4 mm. Based on the result obtained, it was observed that this approach provides fast computation time and efficient solution.

Abstract: The present work is on the synthesis of forsterite (Mg₂SiO₄) powder using talc and magnesium oxide powders as the starting materials followed by a heat treatment process. Sintering behavior and mechanical properties of the forsterite bodies were evaluated from 1200°C to 1500°C. Forsterite phase were detected in samples without any secondary phases at all sintering temperatures. A very high fracture toughness of 4.9MPa.m^1/2 and Vickers hardness of 7.1GPa were measured for samples sintered at 1400°C, thus indicating the viability of this ceramic for biomedical application.

Abstract: Nanoscale materials, primarily metallic elements have been proven as suitable solutions for interconnect technology on power semiconductor devices. Nanoscale materials possess high surface energies thus enabling them to be processed at lower temperatures for high temperature applications of more than 500°C. This literature work aims to present a novel silver-aluminium (Ag-Al) nanoalloy die attach paste solution for power semiconductor devices. Ag and Al nanoparticles were pre-mixed into an organic paste system using binders and a surfactant. Viscosity tests concluded that the Ag-Al nanopaste is suitable for mass manufacturing dispensing and screen printing with an average value of 47,800 cps. Thermogravimetric analysis was used to design the sintering profile at 380°C from 10 to 30 minutes. X-ray diffraction analysis detected the formation of Ag2Al and Ag3Al compounds in the post-sintered nanopaste. Scanning electron microscopy and Energy-dispersive X-ray spectroscopy showcased larger grains in the nanopaste microstructure with the passage of sintering time. The electrical conductivity of the Ag-Al nanopaste decreased as the stencil printed paste thickness increased between 25.4-101.6 microns. This was due to the much larger pore formation in the thicker nanopaste layers during sintering and organics burn off.

Abstract: In this research, composites containing 10-50 vol% SiC whiskers reinforced Cu matrix were fabricated using powder metallurgy technique. The mixtures were blended in a ball milling machine with the addition of ethanol for 2 hours at 150 rpm. The mixtures were allowed to dry in an oven at temperature of 40 °C. Then, the mixtures were uniaxially compacted into a cylindrical pallet of Φ 13.5 x 2 mm under compaction pressure of 472 MPa. It was followed by sintering in vacuum furnace at temperatures of 800-950 °C for 4 hours. The density, microhardness, electrical resistivity, thermal conductivity and microscopy analysis of the sintered composites were studied and reported in this paper.

Abstract: Nanoparticles are now essential material to be used in material engineering, medicine and cosmetic application due to their chemical, mechanical and optical properties. Several experiments were designed to investigate the relationship effect of bead size using different bead size (4 mm and 2 mm) at fix grinding conditions. Changes in particles size produce were studied using dynamic light scattering method at 25 °C. The z-Average and polydipersity index for each particles size at different grinding were recorded. Using smaller size of zirconia bead will produced smaller size of C. asiatica than using larger bead size. As a result the smallest size particle by mean is 242 nm where 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition at 517 nm shows the smaller particles has a higher percentage of inhibition.

Abstract: Durian skin fibres (DSF) are cellulose-based fibres extracted from the durian peel. This paper present the physical behaviour, chemical structure and crystallinity of the fibres, as observed by environmental scanning electron microscope (ESEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). The characteristic of the natural fibers produces from durian skins are similar with other types of natural fiber. The average diameter and density are 0.299 mm and 1.243 g/cm3, respectively while the crystallinity index is slightly higher than the common fibers. The properties and charecteristic of durian skin fibers are within the propertise of lignocellulosic fiber which is suitable for development of biocomposite materials.

Abstract: Electron beam melting (EBM) is a direct metal additive manufacturing technique which has been recently utilized for fabrication of biomedical implants. This paper represents an investigation into the mechanical properties of both as-built and hot isostatic pressing (HIP) processed samples manufactured in EBM process. The titanium alloy, Ti6Al4V was used, which is one of the most common materials for biomedical implants due to its high strength to weight ratio, corrosion resistance, and its biocompatibility features. Tensile properties, surface roughness, and Vickers microhardness have been investigated.