Anasyida Abu Seman

Wear behaviour of eutectic and hypoeutectic Al‐Si‐Mg‐Ce alloys

Purpose – The purpose of this paper is to study the wear behaviour of eutectic and hypoeutectic Al‐Si‐Mg‐Ce alloys.Design/methodology/approach – The eutectic and hypoeutectic alloys were prepared using permanent mould casting process by varied cerium (Ce) addition in the alloy from 1 to 3 wt%. Dry sliding wear tests were performed against a hardened carbon steel (Fe‐2.3%Cr‐0.9%C) using a pin‐on‐disc configuration with fixed sliding speed of 1 m/s and load 50 N at room temperature of ∼25 degree. Morphologies of both worn surfaces and collected debris were characterised by a scanning electron microscope (SEM) equipped with an energy dispersive X‐ray spectrometer (EDS).Findings – It was revealed that following the addition of cerium, intermetallic Al4Ce needle‐like structure was present in eutectic alloys whereas CeMg2Si2 blocky phase was present in the hypoeutectic alloys. The increasing of Ce addition up to 3.0 wt% in hypoeutectic alloy led to formation of AlCe3 intermetallic phase. The increase in cerium ...

Mechanical Properties of Friction Stir Processed 1100 Aluminum Reinforced with Rice Husk Ash Silica at Different Rotational Speeds

This paper presents a study on friction stir processed 1100 aluminum withincorporation of rice huskash derived, amorphous silica particles and fabricated at different tool rotational speeds. During friction stirring amorphous silica powder was placed into a groove made in the joining line of Al 1100 plates. Friction stirringwas performed with clockwise tool rotational speeds of 600 rpm, 865 rpm, 1140 rpm or 1500 rpm with a constant 45 mm/min travelling speed and a 2° tilt angle. High rotational speed (1140 rpm) facilitated material flow in the stir zone, contributing to fine aluminum matrix grain size (30- 10μm) as a result of dynamic recrystallization. Stirring at this rotational speed also caused the fracturingrelated refinement of silica particles to 10μm particle sizethat isassociated with good distribution in the aluminum matrix. Reduction in wear rate of friction stir processed Al1100 with improved hardness was believed to be due to the presence of hard silicawith high interfacial strength and high hardness of recrystallized aluminum grains in the stir zone.

Optimization Processing Parameter of 6061-T6 Alloy Friction Stir Welded Using Taguchi Technique

Taguchi approach was applied to evaluate the processing parameter to determine the most influential control factors which will yield better tensile strength of friction stir welded joint of 6061-T6 aluminium alloy. The processing parameters involved are tool shoulder diameter, in mm (18 ,20, 22), tool rotational speed, in rpm (410, 865, 1140), and feed rate, in mm/min (22, 32, 45). Taguchi parametric design and optimization approach was used. Through the Taguchi parametric design approach, the optimum levels of process parameters were determined. The results indicate that the shoulder size, rotational speed, and feed rate are the significant parameters influencing the tensile strength and hardness of the joint. The predicted optimal values of tensile strength 6061-T6 aluminium alloy is 321.16 MPa. The results was confirmed by further experiments, where the experimented values for tensile strength is 301.28 MPa.

Selection of sample dipping time in liquid nitrogen prior to cryorolling for Al 1100 alloy

This paper aims to study the suitable dipping time in liquid nitrogen prior to cryorolling for Al 1100 alloy at various pre-treatment. The samples were annealed at 250 ˚C for 2 hours and solution treated at 540 ˚C for 1 hour before cryorolling. The pre-treatment Al 1100 sheet alloy was rolled up to 50 % reduction after dipped at various dipping times in liquid nitrogen. The samples were evaluated through hardness and tensile tests performed at room temperature. The suitable dipping times of annealed and non-annealed Al 1100 sheet alloy were 30 minutes as the hardness, tensile and yield strength were the highest.

Effects of body formulation and firing temperature to properties of ceramic tile incorporated with electric arc furnace (EAF) slag waste

Significant quantities of sludge and slag are generated as waste materials or by-products from steel industries. One of the by-products is Electric Arc Furnace (EAF) steel slag which consists of oxides such as CaO, Al2O3 and FeO. This makes it possible for slag to partially replace the raw materials in ceramic tile production. In our preliminary assessment of incorporating the EAF slag into ceramic tile, it was revealed that at fixed firing temperature of 1150°C, the tile of composition 40 wt.% EAF slag – 60 wt.% ball clay has comparable properties with commercial ceramic tile. Thus, this current study would focus on effects of body formulation (different weight percentages of K-feldspar and silica) and different firing temperatures to properties of EAF slag added ceramic tile. EAF slag from Southern Steel Berhad (SSB) was crushed into micron size (EAF slag content was 40 wt.%) and milled with ball clay, K-feldspar and silica before compacted and fired at 1125°C and 1150°C. The EAF slag added tile was cha...

Dissolution Method of Aluminum Foams Containing Mg Using Carbamide Space Holder

This study investigated the properties of aluminium foam containing Mg with various amount of space holder. Aluminum foam was fabricated using dissolution method with various amount of carbamide (20, 40 and 60 wt. %). Aluminum foam with 60 wt. % carbamide has the lowest density (0.68 g/cm3) and exhibited the highest porosity (74.97%). However, the results indicates that aluminum foam with 40 wt. % of carbamide have good compressive and energy absorption with acceptable density and porosity value.

The Effect of Dipping Time of Liquid Nitrogen on Mechanical Properties of Al Alloy 5083 via Cryorolling

Cryorolling is indeed a very suitable approach in producing a good Al alloy of Al 5083 with exceptionally strong and hard properties. This new Severe Plastic Deformation (SPD) methods can bring out the utmost of strength in Al alloy compare with cold rolling. This paper hence discussed the effect of dipping duration of Al alloy in liquid nitrogen prior to rolling process to its improved mechanical properties such as hardness and tensile strength. The result showed that the hardness increased with increasing dipping time until 60 minutes for low temperature pre-anneal and 30 minutes for high temperature pre-anneal and later dropped. The tensile strength of cryorolled sample also showed some improvement for about 5-8% compared with normal cold rolling.

Development of ultrafine-grained 1100 aluminum alloy by cryorolling with the optimized initial heat treatment conditions

The aims of this study to determine the suitable initial heat treatment for 1100 aluminum alloy prior to cryorolling process and the properties of annealed and cryorolled annealed sample. The samples were annealed at different annealing temperature of 200˚C, 250˚C, 300˚C, 350˚C and 400˚C for 2 hours soaking time before cryorolling. The annealing samples then were cryorolled up to 50% thickness reduction after dipping in liquid nitrogen for 30 minutes. The effect of annealing temperature on cryorolled sample was investigated by employing hardness measurements and tensile test. The highest hardness and tensile properties achieved for sample annealed at 250 °C. The entire cryorolled sample showed severely deformed grain which are elongated along and following the rolling direction.

Chemical, Thermal and Phase Analysis of Malaysia’s Electric Arc Furnace (EAF) Slag Waste

This study aims to characterize and investigate properties of EAF slag waste obtained from Southern Steel Berhad, Penang (one of Malaysia’s largest steel makers), prior to its recycling into valuable products. Before characterization, lump form of the EAF slag was crushed into micron size powder. The properties investigated were loss of ignition (L.O.I.), chemical composition, leaching behavior, thermal properties and mineral phases present. Through XRF characterization, the chemical composition of the EAF slag was obtained. The slag was found to have extremely low L.O.I. (0.01 wt.%). Leaching test proved the slag is non-hazardous and safe to be handled. Meanwhile, thermal analysis (TGA) revealed the EAF slag is thermally stable and unlikely to decompose upon heating. Phase identification and quantification were performed by applying Rietveld refinement method. The EAF slag consisted of gehlenite (Al2O3.2CaO.SiO2 – 45.3 wt.%), larnite (2CaO.SiO2 – 21.0 wt.%), hematite (Fe2O3 – 13.4 wt.%) and wustite (FeO – 20.3 wt.%) mineral phases. The XRD profile fitted well with agreement indices of the refinement (Rwp: 6.658 and GOF: 2.588). The properties investigated in this study are expected to shed lights in evaluating the potential recycling of the EAF slag into various valuable products such as aggregate, brick, ceramic tile and cementing material.

Effect of Aluminium and Silicon to IMC Formation in Low Ag-SAC Solder

The effect of Al and Si addition on IMC formation at the solder and Cu substrate interface was investigated. The compositions of the solder alloy used are Sn-0.3 wt.% Ag-0.5 wt.% Cu (SAC0305), SAC0305-1 wt.% Al (SAC0305-1Al), SAC0305-2 wt.% Al (SAC0305-2Al) and SAC0305-2 wt.% Al-2 wt.% Si (SAC0305-2Al-2Si). Solder alloys were prepared by casting process. Melting temperature of each solder alloys was determined using DSC. Reflow process of the solder alloys were carried out at 260 oC on Cu substrate. Morphology of the intermetallic compound (IMC) formed at the solder joint was observed using Fe-SEM equipped with EDX. The addition of Al and Si reduced the thickness of IMC layer formed at the solder joint. The addition of 1.0 wt.% Al formed planar shape of IMC while the addition of 2.0 wt.% Al and 2.0 wt.% Al with 2.0 wt.% Si formed scallop shape of IMC. This is due to Cu-Al IMC and Ag-Al IMC scattered near the interface that act as diffusion barriers to Sn diffusion. This suggests that the addition of right amount of Al and Si could form thinner IMC layer that could lead to increase of reliability of solder interconnect.