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The Tribological And Electrochemical Behavior Of Hvof-Sprayed Cr3c2-Nicr Ceramic Coating On Carbon Steel May 2015

The Tribological And Electrochemical Behavior Of Hvof-Sprayed Cr3c2-Nicr Ceramic Coating On Carbon Steel

Faculty of Engineering University of Malaya

High Velocity Oxygen Fuel (HVOF) is an excellent approach to prepare a good, wear-resistant lamella of Chromium Carbide-Nickel Chrome (Cr3C2-NiCr) on carbon steel for high temperature application. This research investigates the effect of a thin, deposited layer of Cr3C2-NiCr on carbon steel in terms of wear and corrosion properties. The microstructure of the HVOF-sprayed Cr3C2-NiCr coating was characterized at each step by scanning electron microscopy. Wear testing was performed with a pin-on-disk tester. Wear weight loss was examined by applying different loads over a 9048.96 m sliding distance. Experimental results show that the wear resistance of the coated sample ...


A Novel Combined Severe Plastic Deformation Method For Producing Thin-Walled Ultrafine Grained Cylindrical Tubes Mar 2015

A Novel Combined Severe Plastic Deformation Method For Producing Thin-Walled Ultrafine Grained Cylindrical Tubes

Faculty of Engineering University of Malaya

A novel severe plastic deformation (SPD) process entitled combined parallel tubular channel angular pressing (PTCAP) and tube backward extrusion (TBE) is proposed for producing thin-walled ultrafine-grained (UFG) tubes. In this new combined SPD approach, the PTCAP and TBE processes are consequently applied to the tube material in which a severe plastic strain is applied to produce a UFG thin-walled tube. This technique was performed on an AZ31 magnesium tube, and a remarkable grain refinement was achieved. The results showed that this method could easily produce a high strength thin walled tube. The microhardness increased significantly to 70 HV after the ...


Redox Stable Anodes For Solid Oxide Fuel Cells, Guoliang Xiao, Fanglin Chen Mar 2015

Redox Stable Anodes For Solid Oxide Fuel Cells, Guoliang Xiao, Fanglin Chen

Fanglin Chen

Solid oxide fuel cells (SOFCs) can convert chemical energy from the fuel directly to electrical energy with high efficiency and fuel flexibility. Ni-based cermets have been the most widely adopted anode for SOFCs. However, the conventional Ni-based anode has low tolerance to sulfur-contamination, is vulnerable to deactivation by carbon build-up (coking) from direct oxidation of hydrocarbon fuels, and suffers volume instability upon redox cycling. Among these limitations, the redox instability of the anode is particularly important and has been intensively studied since the SOFC anode may experience redox cycling during fuel cell operations even with the ideal pure hydrogen as ...


Dissimilar Friction Stir Welding Between Polycarbonate And Aa 7075 Aluminum Alloy Mar 2015

Dissimilar Friction Stir Welding Between Polycarbonate And Aa 7075 Aluminum Alloy

Faculty of Engineering University of Malaya

In this paper, the effects of process parameters, such as the tool rotational and traverse speeds, on temperature evolution and the microstructural and mechanical properties of dissimilar friction stir welding between 3 mm thick AA 7075 aluminum alloy and polycarbonate (PC) plates were investigated. The tool rotational and traverse speeds were varied from 3 000 to 3 500 rpm and 50 to 150 mm min(-1), respectively. The joint fabricated at 3 250 rpm and 100 mm min(-1) yielded a highest tensile load of 586 N. Microstructural analysis of the stir zone revealed an interlock phenomenon, the transportation of ...


Microstructure And Mechanical Properties Of Multipass Friction Stir Processed Aluminum Silicon Carbide Metal Matrix, Innovative Research Publications Irp India, V V Murali Krishna G, K.S Atyanarayana Feb 2015

Microstructure And Mechanical Properties Of Multipass Friction Stir Processed Aluminum Silicon Carbide Metal Matrix, Innovative Research Publications Irp India, V V Murali Krishna G, K.S Atyanarayana

Innovative Research Publications IRP India

In this study, SiC particles were incorporated by using Friction Stir Processing (FSP) into the 6351 aluminium alloy to form particulate composite materials. Sampels were subjected to constant rotational and traverse speeds of the FSP tool with and without SiC reinforcements. Microstructural observations were carried out by employing optical microscopy of the modifiedsurfaces. Mechanical properties were evaluated by tensile test on UTM. For the 100% overlapping, No.of passes caused grain modification in the processed zone. The tensile test results indicate an improvement of strength and Microhardness for Single Pass FSP samples and a reduction in the strength of FSP ...


Fuzzy Logic Based Model For Predicting Surface Roughness Of Machined Al-Si-Cu-Fe Die Casting Alloy Using Different Additives-Turning Jan 2015

Fuzzy Logic Based Model For Predicting Surface Roughness Of Machined Al-Si-Cu-Fe Die Casting Alloy Using Different Additives-Turning

Faculty of Engineering University of Malaya

This paper presents a fuzzy logic artificial intelligence technique for predicting the machining performance of Al-Si-Cu-Fe die casting alloy treated with different additives including strontium, bismuth and antimony to improve surface roughness. The Pareto-ANOVA optimization method was used to obtain the optimum parameter conditions for the machining process. Experiments were carried out using oblique dry CNC turning. The machining parameters of cutting speed, feed rate and depth of cut were optimized according to surface roughness values. The results indicated that a cutting speed of 250 m/min, a feed rate of 0.05 mm/rev, and a depth of cut ...


Investigating The Machinability Of Al-Si-Cu Cast Alloy Containing Bismuth And Antimony Using Coated Carbide Insert Jan 2015

Investigating The Machinability Of Al-Si-Cu Cast Alloy Containing Bismuth And Antimony Using Coated Carbide Insert

Faculty of Engineering University of Malaya

Surface roughness and cutting force are two key measures that describe machined surface integrity and power requirement evaluation, respectively. This investigation presents the effect of melt treatment with addition of bismuth and antimony on machinability when turning Al-11% Si-2% Cu alloy. The experiments are carried out under oblique dry cutting conditions using a PVD TIN-coated insert at three cutting speeds of 70, 130 and 250 m/min, feed rates of 0.05, 0.1, 0.15 mm/rev, and 0.05 mm constant depth of cut. It was found that the Bi-containing workpiece possess the best surface roughness value and ...


Investigating The Electrical Discharge Machining (Edm) Parameter Effects On Al-Mg2si Metal Matrix Composite (Mmc) For High Material Removal Rate (Mrr) And Less Ewr-Rsm Approach Jan 2015

Investigating The Electrical Discharge Machining (Edm) Parameter Effects On Al-Mg2si Metal Matrix Composite (Mmc) For High Material Removal Rate (Mrr) And Less Ewr-Rsm Approach

Faculty of Engineering University of Malaya

Al-Mg2Si composite is a new group of metalmatrix composites (MMCs). Electrical discharge machining (EDM) is a nonconventional machining process for machining electrically conductive materials regardless of hardness, strength and temperature resistance, complex shapes, fine surface finish/textures and accurate dimensions. A copper electrode and oil-based dielectric fluid mixed with aluminum powder were used. The polarity of electrode was positive. Response surface methodology (RSM) was used to analyze EDM of this composite material. This research illustrates the effect of input variables (voltage, current, pulse ON time, and duty factor) on material removal rate (MRR), electrode wear ratio (EWR), and microstructure changes ...


Failure Analysis Of Superheater Tube Supports Of The Primary Reformer In A Fertilizer Factory Jan 2013

Failure Analysis Of Superheater Tube Supports Of The Primary Reformer In A Fertilizer Factory

A.S. Md Abdul Haseeb

Eutectic Sn-Bi alloy is gaining considerable attention in the electronic packaging industry because of its favorable properties such as low melting temperature, good wettability, and good mechanical properties. Miniaturization of electronic devices requires small solder bumps, a few tens of micrometers in diameter. Electrodeposition is a reliable technique for the deposition of small volume of solder. This work focuses on the formation of eutectic Sn-Bi solder by reflowing a metal stack containing sequentially electrodeposited Sn and Bi layers. The effects of layering sequence on the composition and microstructure of the resulting alloy is investigated. Irrespective of the layering sequence, a ...


A Semi-Empirical Model To Predict The Acoustic Behaviour Of Fully And Partially Reticulated Polyurethane Foams Based On Microstructure Properties, Olivier Doutres Ph.D., Noureddine Atalla Apr 2012

A Semi-Empirical Model To Predict The Acoustic Behaviour Of Fully And Partially Reticulated Polyurethane Foams Based On Microstructure Properties, Olivier Doutres Ph.D., Noureddine Atalla

Olivier Doutres Ph.D.

This work investigates the links between the microstructure of polyurethane foams and their sound absorbing efficiency, and more specifically the effect of membranes closing the cells. In a previous work, the authors proposed a semi-empirical approach to link the foam microstructure properties, i.e. reticulation rate, strut length and thickness, with its non-acoustic parameters. The study was based on the complete characterization of 15 isotropic polyurethane foams with various cell sizes and reticulation rates (i.e. open pore content). This paper proposes a validation of this semi-empirical model using 3 new polyurethane foams, not used in the first characterization set ...


Effects Of Addition Of Copper Particles Of Different Size To Sn-3.5ag Solder Dec 2011

Effects Of Addition Of Copper Particles Of Different Size To Sn-3.5ag Solder

A.S. Md Abdul Haseeb

No abstract provided.


Thermal Stability Of Electrodeposited Liga Ni-W Alloys For High Temperature Mems Applications Jan 2008

Thermal Stability Of Electrodeposited Liga Ni-W Alloys For High Temperature Mems Applications

A.S. Md Abdul Haseeb

For thermally stable LIGA materials for high temperature MEMS applications LIGA Ni-W layers and micro testing samples with different compositions (15 and 5 at% W) were electrodeposited. In order to investigate the thermal stability the Ni-W layers were annealed at different temperatures (300-700°C) and for different durations (1, 4, 16 h). Their microstructure and micro-hardness were than analysed after annealing and compared with those of as-deposited states. The observed microstructures show, in comparison to pure LIGA nickel, a small grain growth and a relatively stable structure up to 700°C. The micro-hardness values of the LIGA Ni-W layers are ...


Study Of The Wear Behaviour Of Al-4.5% Cu-3.4% Fe In Situ Composite: Effect Of Thermal And Mechanical Processing Feb 2007

Study Of The Wear Behaviour Of Al-4.5% Cu-3.4% Fe In Situ Composite: Effect Of Thermal And Mechanical Processing

A.S. Md Abdul Haseeb

Al-Cu-based MMCs reinforced by Al-Fe intermetallics are investigated for their wear behaviour. The composite (Al-4.5 mass% Cu-3.4 mass% Fe) was produced by solidification processing where the Al-Fe-based intermetallic formed in situ in a matrix of mainly Al-Cu alloy. The effects of thermal and mechanical processing, viz., as-cast condition, solution treatment, aging and hot rolling on the wear behaviour of the composites were examined. The composites were characterized by optical microscopy, SEM, microhardness measurements and X-ray diffraction. The wear behaviour of the composites was studied in a pin-on-disc type wear apparatus. The as-cast in situ composite exhibited the highest ...


Failure Analysis Of Superheater Tube Supports Of The Primary Reformer In A Fertilizer Factory Jan 2005

Failure Analysis Of Superheater Tube Supports Of The Primary Reformer In A Fertilizer Factory

A.S. Md Abdul Haseeb

A failure analysis of superheater tube supports of the primary reformer in a local fertilizer factor is presented. A number of tube supports failed at approximately half of their designed service life. Following the failure, the factory was visited, and relevant information and samples were collected. The samples were investigated in the laboratory by chemical analysis, macro- and microhardness measurements, macro-and micrometallographic examinations, and X-ray diffractometry. The analysis showed the supports were fabricated from HH-type heat-resisting alloy and that the failure mode was high-temperature creep. The microstructure of the alloy showed the presence of massive intergranular as well as intragranular ...


Wear Failure Of A Leaded Bronze Bearing: Correlation Between Plant Experience And Laboratory Wear Test Data Jun 2003

Wear Failure Of A Leaded Bronze Bearing: Correlation Between Plant Experience And Laboratory Wear Test Data

A.S. Md Abdul Haseeb

This paper describes an investigation on the failure of a large leaded bronze bearing that supports a nine-ton roller of a plastic calendering machine. At the end of the normal service life of a good bearing, which lasted for seven years, a new bearing was installed. However the new one failed catastrophically within a few days, generating a huge amount of metallic wear debris and causing pitting on the surface of the cast iron roller. Following the failure, samples were collected from both good and failed bearings. The samples were analyzed chemically and their microstructures examined. Both samples were subjected ...


Wear Failure Of A Leaded Bronze Bearing: Correlation Between Plant Experience And Laboratory Wear Test Data Jun 2003

Wear Failure Of A Leaded Bronze Bearing: Correlation Between Plant Experience And Laboratory Wear Test Data

A.S. Md Abdul Haseeb

This paper describes an investigation on the failure of a large leaded bronze bearing that supports a nine-ton roller of a plastic calendering machine. At the end of the normal service life of a good bearing, which lasted for seven years, a new bearing was installed. However the new one failed catastrophically within a few days, generating a huge amount of metallic wear debris and causing pitting on the surface of the cast iron roller. Following the failure, samples were collected from both good and failed bearings. The samples were analyzed chemically and their microstructures examined. Both samples were subjected ...


Wear Failure Of A Leaded Bronze Bearing: Correlation Between Plant Experience And Laboratory Wear Test Data Jun 2003

Wear Failure Of A Leaded Bronze Bearing: Correlation Between Plant Experience And Laboratory Wear Test Data

A.S. Md Abdul Haseeb

This paper describes an investigation on the failure of a large leaded bronze bearing that supports a nine-ton roller of a plastic calendering machine. At the end of the normal service life of a good bearing, which lasted for seven years, a new bearing was installed. However the new one failed catastrophically within a few days, generating a huge amount of metallic wear debris and causing pitting on the surface of the cast iron roller. Following the failure, samples were collected from both good and failed bearings. The samples were analyzed chemically and their microstructures examined. Both samples were subjected ...