Papers by Keyword: Fabrication

Abstract: One of the main problems with the use of steels for elevated temperatures is their limited weldability. This is mainly due to the fact that these materials may contain in their chemical composition. Due to the susceptibility to cold cracking, PWHT is necessary, especially in high-stiffness welded structures. In addition, depending on the condition after heat treatment or in the absence of heat treatment, precipitates may appear in the microstructure of the steel, affecting its mechanical properties. It is important in this case to ensure the high quality of welded joints, which means that the manufacturer has to demonstrate a very high technical culture. Currently, thin-walled pipe butt joints are welded manually using a tungsten electrode with solid wire material (TIG method). One of the solutions that can significantly speed up the welding process of components for work at elevated temperatures is the use of an electron beam welding. In addition, the ability to make welded joints without the use of filler material and to achieve narrow heat-affected zones may find application in the welding of modern materials used in the power industry. This paper presents the welding experience of materials assigned for the power industry (TEMPALOY AA1 and T92) by use of electron beam. In this article authors present the results of tests gained during first steps of welding welded joints. The article also includes preliminary results on the service life of the fabricated joints.

Abstract: The world is moving towards the renewable energy generation and utilization. The machinery, tools have been now updated to cope up with the environmental need including sustainability and environmental protection. From Gasoline to hybrid and Electric Vehicles have also been introduced. The material of the vehicles has also been made light weighted so that the efficiency of the vehicle can also be enhanced. On the other side if the vehicle body gets dents, scratches or even bumps so they need to be either repair and mostly new parts are installed like fender, bumper or bonnets and hoods. In this regards a dent remover is designed with the facility to remove the dent even without the removal of the paint that is a paintless dent remover. This Paintless dent remover is also equipped with the ability to work on different angles which another dent remover could not with in the facility. The angular dent removing facility provide a wider span of work and better efficiency respectively. Finite Element Analysis and simulation is also necessary for a successful design, so it is also done and from FEAit was found that the dent remover can easily pulled a dent with a maximum force of 100 kg. After successful simulation and designing the Dent remover is also put forward for fabrication so that it may give a large range of dent removing facility in real time.

Abstract: Vertical high-voltage 4H-SiC superjunction (SJ) MOSFETs have emerged as a superior alternative compared to conventional SiC MOSFET or Si IGBT, as SJ MOSFETs present a better trade-off between specific on-resistance (R_ON,sp) and breakdown voltage (BV). The fabrication of SJ devices requires precise, and multi-step processes, such as multi-epitaxial growth, trench-refill processes, and MeV implantations [3,4,5]. However, these methods increase the overall costs of SJ devices compared to their conventional counterparts, potentially undermining their benefits. This paper compares the chip costs of SJ and conventional MOSFETs at a wide range of BV and current ratings, evaluating the economic feasibility of SJ MOSFETs in 4H-SiC. Our results highlight the potential improvements in SJ fabrication and design to enhance cost-effectiveness, particularly for medium-voltage applications (>3.3kV).

Abstract: One of the most significant environmental challenges nowadays is the rising manufacturing of non-biodegradable polymer wastes like polystyrene. In order purpose of manufacture environmentally friendly polystyrene that easily decomposes, a solvent approach was used to create polystyrene based zinc oxide- graphite composites. The surface morphology and materials contained in the modified polystyrene were evaluated by scanning electron microscopy-energy dispersive X-ray analysis to verify the dispersion and distribution of the nanoparticles by scanning electron microscopy and the material contents by energy dispersive X-ray analysis. While the crystal structure, chemical bonds, and functions were determined by X-ray Diffraction and Fourier transform infrared, no change in the chemical structure occurred in polystyrene. Thermogravimetric analysis was used to assess the thermal decomposition. And its results found that the temperature of the decomposition was 46.78° lower in zinc oxide and graphite-based polystyrene composites than in pure polystyrene. It came to light that the presence of zinc oxide nanoparticles causes phase separation and consequently impacts the thermal behaviour of graphite-based polystyrene composites. The phase separation was demonstrated by the Thermogravimetric curves showing two degrading steps. This satisfies the urgent demand to synthesize polystyrene that is eco-friendly and easy to thermally decomposition, as well as easy to recycle, which benefits both the environment and the commercial side.

Abstract: Recycling of aluminium (Al) from waste aluminium scraps for fabricating aluminium casts is a waste management technique suitable for reducing environmental pollution. The aluminium casts can be further processed into different materials of engineering interests such as heater-cooler (thermal) blocks. In this study, the microstructural characterization of aluminium cast fabricated from recycled aluminium waste and adapted for use via the (steady-state technique) as heater-cooler blocks required in the determination of the thermal conductivity of conducting solid composites was investigated. The characterization was investigated using the Scanning Electron Microscopy (SEM), Energy Displacer Spectroscopy (EDS), X-ray Diffractometer (XRD), and X-ray Fluorescence (XRF). The XRD result confirms the crystalline structure of aluminium on the fabricated aluminium cast. The elemental composition results confirmed that the fabricated cast contains 90% Al, with Silicon (Si) accounting for about 8% of the chemical composition while the remaining 2% was contributed by C, O, Fe, Zn, and Cu. The compositional change observed during characterization was attributed to the recycling process used in fabricating the aluminium cast.

Abstract: In an increasingly electrified technology driven world, power electronics is central to the entire clean energy manufacturing economy. Silicon (Si) power devices have dominated power electronics due to their low cost volume production, excellent starting material quality, ease of fabrication, and proven reliability. Although Si power devices continue to improve, they are approaching their operational limits primarily due to their relatively low bandgap, critical electric field, and thermal conductivity that result in high conduction and switching losses, and poor high temperature performance. Silicon Carbide’s (SiC) compelling efficiency and system benefits have led to significant development efforts over the last two decades and today planar and trench MOSFETs, and JFETs are commercially available from several vendors as discrete components or in high power modules in the of 650 V to 1700 V voltage range. High impact application opportunities, where SiC devices are displacing their incumbent Si counterparts, have emerged and include automotive and rail power electronics with reduced losses and reduced cooling requirements; novel data center topologies with reduced cooling loads and higher efficiencies; variable frequency drives for efficient high power electric motors at reduced overall system cost; more efficient, flexible, and reliable grid applications with reduced system footprint; and “more electric aerospace” with weight, volume, and cooling system reductions contributing to energy savings. In particular, SiC insertion in electric vehicles brings major competitive advantages and is a volume application opportunity that can spur manufacturing economies of scale and lower system costs. As SiC continues to grow, the industry is lifting the last barriers to mass commercialization that include higher than Si device cost, relative lack of wafer planarity, the presence of basal plane dislocations, reliability and ruggedness concerns, and the need for a workforce skilled in SiC power technology to keep up with the rising demand. It should be noted that in many applications, insertion of SiC reduces overall system cost compared to Si even though SiC devices can cost 2-3 more than their Si counterparts. This is due to the passive component and cooling system simplifications enabled by the efficient high frequency SiC operation. In this paper, we will review key aspects of SiC technology and discuss overcoming barriers to mass commercialization.

Abstract: In the present article aluminium matrix composites were fabricated by cold pressing and sintering technique. Multi-walled carbon nanotube (MWCNT) with various weight percentage 0.5, 1.0, 1.5 and 2.0 were added as a reinforcement to aluminium (Al) matrix. A planetary ball mill was used for mechanical alloying and even dispersion of carbon nanotubes (CNTs) in aluminium matrix. Tin (Sn) with 1.0 weight percent was used in composite to incite the sintering. The sintering was carried out at 500°C inside a tube furnace in an argon atmosphere. The morphology and structure of CNT and Al-Sn-CNT composite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. The effect of MWCNT reinforcement on microhardness and wear properties of Al-Sn-CNT composite was investigated. The hardness of composites was improved significantly with increase in CNT fraction. The reduction in the coefficient of friction and improvement in the wear resistance of the Al-Sn-CNT composite was noticed with the increase in percentage of CNTs in the composite.

Abstract: Fiber metal laminate (Glare) made of 2014-T6 aerospace aluminum alloy sheets adhesively bonded with E-glass fiber based composite prepregs is investigated in the paper. The fabrication procedure of the laminate is explained. Chemical composition, macrostructure and residual stress of aluminum alloy are obtained. Mechanical properties of the laminate viz. tensile, flexural and shear strengths are measured.

Abstract: This paper is related to the problem of enhancing the optical and functional performance of luminescent gas sensors via its excitation by photonic nanojets. The novel sensor structure consisting of the array of alumina microparticles covered by optical sensitive layer was designed. The parameters of the photonic nanojets generated in both transmission and reflection modes has been numerically end experimentally studied. It was shown that PNJ in reflection mode demonstrates an unexpectedly high enhancement of photoluminescence. It was obtained that the excitation of the sensitive layer by photonic nanojets extends the limit of gaseous ammonia detection up to 0.1 ppm for reflection mode and up to 0.02 ppm for transmission mode.

Abstract: Computer numerical control (CNC) machine has greater utility in the modern advanced industrial field. This paper deals with the parametric effects such as spindle speed (1500-2100 rpm) (N) (X1), depth of cut (DOC) (0.15-0.55 mm) (X2) and feed rate (f) (30-50 mm/min) (X3) on machining characteristics like tool wear rate (TWR) and surface roughness (Ra) during fabrication of IS-617 Aluminum miniature component by advanced CNC lathe using Tungsten-carbide tool. The article analyzes the second-order mathematical model development with co-relation of co-efficient of regression (COR) and analysis of variances (ANOVA) using desirability function analysis during the production of the miniature segment. The paper also consists of multi-criteria optimization for achieving the optimal parametric combination for minimum surface roughness and tool wear rate for this manufacturing operation. The paper also shows the fabricated micro-product of Aluminum at the optimal parametric conditions using CNC programming. It is found that spindle speed has a greater effect on the tool wear rate and depth of cut has dominating effects on surface roughness of job specimen. Desirability parametric combination for minimized surface roughness as well as tool wear rate has been found 1523 rpm/0.15mm/30mmmin-1.