Microstructure Evolution of Conventional and Semi-Solid Cast of A356 Aluminium Alloy with Addition of Inoculant

2015 ◽  
Vol 819 ◽  
pp. 25-30 ◽  
Author(s):  
M.N. Laila Masrur ◽  
M. Syukron ◽  
H. Zuhailawati ◽  
A.S. Anasyida
Keyword(s):  
Aluminium Alloy ◽  
Dendritic Structure ◽  
A356 Alloy ◽  
Optical Microscope ◽  
Globular Structure ◽  
Average Grain Size ◽  
Semi Solid ◽  
Vicker’S Microhardness ◽  
Steel Mould ◽  
A356 Aluminium Alloy

This paper investigated the effect of inoculant, Al-5Ti-1B in conventional and semi-solid casting A356 aluminium alloy. A356 aluminium alloy was melted at 850 oC and poured at 680 °C directly into the steel mould and on the inclined slope into steel mould. Inoculant was added in various percentages of 1 wt.%, 2 wt.%, 3 wt.% and 3.5 wt.% in A356 aluminium alloy melt. Microstructure and microhardness were characterized using optical microscope and Vicker’s microhardness tester. The addition of master alloy up 3.5 wt.% Al-5Ti-1B in conventional casting refined dendritic structure with average grain size of 33.41 μm. The microstructures of semi-solid A356 aluminium alloy with addition of Al-5Ti-1B consist of equiaxed structure of α-Al. Further addition of Al-5Ti-1B refined the globular structure of α-Al. The higher hardness was achieved for A356 alloy prepared using semi-solid with addition of 3.5 wt.% of Al-5Ti-1B.

Effect of Grain Refiner on Microstructure of Semi-Solid A356 Aluminium Alloy

2014 ◽  
Vol 1024 ◽  
pp. 251-254 ◽  
Author(s):  
Mohd Nasir Laila Masrur ◽  
Anasyida Abu Seman ◽  
Hussain Zuhailawati
Keyword(s):  
Aluminium Alloy ◽  
Master Alloy ◽  
Optical Microscope ◽  
Grain Refining ◽  
Grain Refiner ◽  
Inclined Slope ◽  
Semi Solid ◽  
Vicker’S Microhardness ◽  
Steel Mould ◽  
A356 Aluminium Alloy

Grain refining has been studied in the semi-solid-metal (SSM) casting by addition of master alloy Al-5Ti-1B using inclined slope. A356 aluminium alloy was melted at 850 °C and poured at 660 °C on the inclined slope into the steel mould. Grain refiner was added in various percentages of 0.2%, 0.5% and 1.0% in A356 aluminium alloy melt. Microstructure and microhardness were characterized using optical microscope and Vicker’s microhardness tester. The addition of master alloy Al-5Ti-1B not only refined but also increased the globularity of the primary α-Al particles. The higher hardness was achieved with 1% addition of master alloy Al-5Ti-1B.

Microstructure Evolution of Conventional and Semi-Solid A356 Alloy with Addition of Strontium

2015 ◽  
Vol 1087 ◽  
pp. 488-492
Author(s):  
Yuan Sieng Seo ◽  
Laila Masrur Mohd Nasir ◽  
Hussain Zuhailawati ◽  
Anasyida Abu Seman
Keyword(s):  
Phase Analysis ◽  
Eutectic Alloy ◽  
Cast Alloy ◽  
Dendritic Structure ◽  
A356 Alloy ◽  
Melting Furnace ◽  
Eutectic Structure ◽  
Globular Structure ◽  
Semi Solid ◽  
Steel Mould

In this study, modification of aluminium silicon eutectic alloy by grain modifier, strontium was investigated on conventional and slope cast A356 alloy. A356 alloy with addition of 0 to 0.97 wt.% Sr was prepared by conventional and slope casting in melting furnace. The molten metal of A356 alloy was casted into steel mould. Microstructure was observed using SEM. Phase analysis was done using XRD. Microhardness was conducted using Vicker microhardness. Microstructure of conventional cast displayed dendritic structure whereas slope cast displayed globular structure. Addition of Sr refined eutectic structure in both conventional and slope cast alloy. Phase analysis revealed the presence of Al2Sr phase in conventional cast Al-6Si-0.97Sr. Microhardness of the conventional cast alloy decreased with increasing of Sr up to 0.97 wt.%.

Study of Microstructural Evolution and Phase’s Morphology after Partial Remelting in A356 Alloy

2008 ◽  
Vol 141-143 ◽  
pp. 367-372 ◽  
Author(s):  
A. Mahdavi ◽  
M. Bigdeli ◽  
M. Hajian Heidary ◽  
F. Khomamizadeh
Keyword(s):  
Dendritic Structure ◽  
A356 Alloy ◽  
Intermetallic Phases ◽  
Effective Parameters ◽  
Dendritic Microstructure ◽  
Globular Structure ◽  
Needle Morphology ◽  
Sima Process ◽  
Semi Solid ◽  
Globular Form

In this work, effective parameters of SIMA process to obtain non dendritic microstructure in A356 alloy were investigated. In addition, the effect of SIMA process on the evolution of morphology of silicon and intermetallic phases in this alloy was studied. Microstructure images obtained from optical microscopy and SEM observation showed that increase in plastic work up to 40% and then holding of samples in the semi solid state at temperature of 580oC, causes that primary dendritic structure changes to non dendritic, fine and globular structure, but optimum reheating time completely depended on initial thickness of samples. If all parameters of SIMA process are the same, the grain boundaries of thinner samples begin to wet and following globalization will be completed in shorter reheating time rather than thicker ones. Moreover, it was found that the intermetallic phases lost their angular or needle morphology and gradually changed to rounded morphology and even to globular form. Also the optimum reheating time thoroughly depends on primary casting microstructure as the finer casting microstructure begin to globalize faster than thicker one under more little stains.

Corrosion Behaviour of the Anodised A356 Aluminium Alloy Produced by the Rheo-High Pressure Die Casting Process

2014 ◽  
Vol 1019 ◽  
pp. 67-73 ◽  
Author(s):  
Levy Chauke ◽  
Kalenda Mutombo ◽  
Gonasagren Govender
Keyword(s):  
High Pressure ◽  
Aluminium Alloy ◽  
Corrosion Behaviour ◽  
Die Casting ◽  
Casting Process ◽  
Optical Microscope ◽  
High Pressure Die Casting ◽  
Semi Solid ◽  
Pressure Die Casting ◽  
A356 Aluminium Alloy

<span><p>Semi-solid metal forming of aluminium alloys has demonstrated the capability to produce near net shaped high integrity components. Anodising of these components for aesthetic and/or improved corrosion resistance is specified by some designers or users of this technology. The corrosion behaviour of fully anodised and partially anodised A356 aluminium alloy plates produced using the CSIR Rheo-High Pressure Die Casting (CSIR-RHPDC) process was investigated using immersion testing in a 3.5% NaCl solution with pH = 7. Optical microscope equipped with image analysis software and scanning electron microscope (SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDS) were used to evaluate the behaviour of the corroded samples. The fully anodised sample showed that the anodised surface displayed some surface degradation. This degradation was more severe on the anodised surface with surface liquid segregation (SLS), but provided sufficient protection to prevent corrosion of the base metal. The partially anodised sample showed severe corrosion of the based metal with the corrosion concentrated in the silicon rich eutectic and SLS regions.</p> <span style="font-family: Times New Roman; font-size: medium;" face="Times New Roman" size="3"> </span>

Microstructure characterization and evaluation of mechanical properties of stir rheocast AA2024/TiB2 composite

2019 ◽  
Vol 54 (7) ◽  
pp. 981-997
Author(s):  
Semegn Cheneke ◽  
D Benny Karunakar
Keyword(s):  
Mechanical Properties ◽  
Dendritic Structure ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Globular Structure ◽  
Cast Sample ◽  
X Ray ◽  
Weight Percentage ◽  
The Matrix ◽  
Fractured Surface

In this research, microstructure and mechanical properties of stir rheocast AA2024/TiB2 metal matrix composite have been investigated. The working temperature was 640℃, which was the selected semisolid temperature that corresponds to 40% of the solid fraction. Two weight percentage, 4 wt%, and 6 wt% of the TiB2 reinforcements were added to the matrix. The field emission scanning electron microscope micrographs of the developed composites showed a uniform distribution of the particles in the case of the 2 wt% and 4 wt% of the reinforcements. However, the particles agglomerated as the weight percentages of the reinforcement increases to 6%. The optical microscope of the liquid cast sample showed the dendritic structure, whereas the rheocast samples showed a globular structure. The X-ray diffraction analysis confirmed the distribution of the reinforcements in the matrix and the formation of some intermetallic compounds. Mechanical properties significantly improved by the addition of the reinforcements in the matrix. An increase in tensile strength of 13.3%, 40%, 28%, and 5% was achieved for the unreinforced rheocast sample, 2 wt%, 4 wt%, and 6 wt% reinforced rheocast samples respectively, compared to the liquid cast sample. An increase in 20% of hardness was attained for the composite with 2 wt% TiB2 compared to the liquid cast sample. According to the fractography analysis, small dimples were observed on the fractured surface of the unreinforced rheocast sample, whereas small and large voids were dominant on the fractured surface of the 2 wt% composite, which shows the ductile fracture mode.

scholarly journals Numerical Simulation and Experimental Investigation of the Preparation of Aluminium Alloy 2A50 Semi-Solid Billet by Electromagnetic Stirring

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5470
Author(s):  
Yongfei Wang ◽  
Shengdun Zhao ◽  
Yi Guo
Keyword(s):  
Numerical Simulation ◽  
Aluminium Alloy ◽  
Deep Understanding ◽  
Electromagnetic Stirring ◽  
Experimental Result ◽  
Maximum Speed ◽  
Operating Parameters ◽  
Average Grain Size ◽  
Semi Solid ◽  
High Level

Electromagnetic stirring (EMS) has become one of the most important branches of the electromagnetic processing of materials. However, a deep understanding of the influence of the EMS on the thermo-fluid flow of the aluminium alloy melt, and consequently the refinement of the microstructure is still not available. This paper investigated the influence of the operating parameters of EMS on the magnetohydrodynamics, temperature field, flow field, and the vortex-shaped structure of the melt as well as the microstructure of the aluminium alloy 2A50 billet by numerical simulation and experiments. The operating parameters were categorised into three groups representing high, medium, and low levels of Lorentz forces generated by EMS. The numerical simulation matched well with the experimental result. It was found that a high level of EMS can improve the uniformity of the temperature and flow fields. The maximum speed was observed at the radius of around 25 mm under all EMS levels. Both the depth and diameter of the vortex-shaped structure generated increased with the enhancement in the EMS level. The average grain size of the edge sample of the billet was reduced by 48.3% while the average shape factor was increased by 51.0% under the medium-level EMS.

Microstructure and Hardness of Friction Welded SSM 356 Aluminium Alloy

2014 ◽  
Vol 887-888 ◽  
pp. 1273-1279 ◽  
Author(s):  
Kulyuth Boonseng ◽  
Chaiyoot Meengam ◽  
Suppachai Chainarong ◽  
Prapas Muangjunburee
Keyword(s):  
Aluminum Alloys ◽  
Aluminium Alloy ◽  
Friction Welding ◽  
Rotational Speed ◽  
Base Material ◽  
Original Structure ◽  
Welding Time ◽  
Globular Structure ◽  
Average Hardness ◽  
Semi Solid

SSM 356 aluminum alloys was obtained from a rheocasting technique named gas induced semi solid process has globular structure on base. The friction welding method conserve microstructure that is similar to the original structure of the base material a globular structure. It is also found that a rotational speed of 1750 RPM, burn of Length of 3.2 millimeters and welding time (upset time) of 30 second can produce a very good weld. The results of the investigation have shown that a have average hardness in the range 58.13 HV.

The Effect of Scandium on the Mechanical Properties of A356 Aluminium Alloy

2016 ◽  
Vol 707 ◽  
pp. 144-147
Author(s):  
Ying Pio Lim ◽  
Wei Hong Yeo ◽  
A. Masita
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminium Alloy ◽  
Die Casting ◽  
A356 Alloy ◽  
Charpy Impact ◽  
Casting Process ◽  
Die Casting Process ◽  
Charpy Impact Strength ◽  
A356 Aluminium Alloy

In this project, the addition of scandium (Sc) into A356 aluminium alloy was studied for its effect on the mechanical properties after gravity die casting process. Scandium addition was administered at the weight percentages of 0.1, 0.2 and 0.3. The results obtained in this work revealed that scandium can significantly enhance the mechanical properties of A356 alloy in terms of tensile strength, hardness and charpy impact strength. In general, the addition of 0.2 wt% Sc in A356 alloy was found to be able to achieve the maximum tensile strength of 172.94MPa as compared to 136.03MPa for sample without Sc. No significant improvement in tensile strength was found when more than 0.3wt% added to the alloy. As for hardness, the sample with 0.3 wt% Sc attained the maximum Vicker’s hardness of 86.60 HV as compared to 76.48 HV for unmodified A356. Similarly, the addition of 0.3wt% Sc in A356 can achieve highest impact energy of 2.71J as compare to 1.09J for unmodified A356.

Laser Welding of SSM Cast A356 Aluminium Alloy Processed with CSIR-Rheo Technology

2006 ◽  
Vol 116-117 ◽  
pp. 173-176 ◽  
Author(s):  
R. Akhter ◽  
L. Ivanchev ◽  
C. Van Rooyen ◽  
P. Kazadi ◽  
H.P. Burger
Keyword(s):  
Mechanical Properties ◽  
Laser Welding ◽  
Weld Metal ◽  
Aluminium Alloy ◽  
Nd:Yag Laser ◽  
Dendrite Structure ◽  
Weld Microstructure ◽  
Semi Solid ◽  
A356 Aluminium Alloy ◽  
Fine Dendrite

Samples of aluminium alloy A356 were manufactured by Semi Solid Metals HPDC technology, developed recently in CSIR-Pretoria. They were butt welded in as cast conditions using an Nd:YAG laser. The base metal and weld microstructure were presented. The effect of different heat treatments on microstructure and mechanical properties of the welds were investigated. It was found that the fine dendrite structure of the weld metal contributed for equalizing the mechanical properties of the joint.

Microstructural Evaluation of Semi-Solid and Thixoformed Parts of LM28 Aluminum Alloy

2012 ◽  
Vol 192-193 ◽  
pp. 136-141
Author(s):  
S.G. Shabestari ◽  
P. Ghaemmaghami ◽  
H. Saghafian ◽  
A. Osanlo
Keyword(s):  
Mechanical Properties ◽  
Morphological Changes ◽  
Physical And Mechanical Properties ◽  
Primary Silicon ◽  
Optical Microscope ◽  
Globular Structure ◽  
Cooling Slope ◽  
The Matrix ◽  
Semi Solid ◽  
Cooling Slope Casting

Attractive physical and mechanical properties of aluminum alloys make them very interesting for the automotive industry. The commercial way for manufacturing LM28 alloy is die-casting, but this process encounters several problems such as shrinkage and gas porosities. Their good mechanical properties and high resistance to wear are because of the presence of hard primary silicon particles distributed in the matrix. Therefore, the size and morphology of primary silicon and also the structure of α-Al particles in hypereutectic Al–Si alloys influence the mechanical properties of the alloys. In this research, a new process of manufacturing of this alloy has been developed using LM28 feedstock produced through cooling slope casting. The feedstocks produced via cooling slope casting had a partial globular structure that contained globules, rosettes and dendrites of α-Al. These feedstocks were thixoformed under three different pressures. The primary dendrites and rosettes changed to globular structure. The microstructure of thixoformed parts contained α-Al globules, small primary Si particles dispersed between these globules, and Al-Si eutectic phase. The mechanism of the formation of α-Al globules by this process was explained. Microstructures of as cast specimens, feedstocks produced via cooling slope, specimens that were heat treated in the semi-solid temperature and thixoformed specimens were studied with optical microscope and image analysis. The morphological changes during these processes were interpreted.

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