Papers by Keyword: A356 Alloy

Abstract: The lightweight composition, non-magnetic nature, and machinability of aluminum alloy A356 make it an important material in many industries due to its significant mechanical properties such as strength, ductility, fatigue resistance, and castability. Aluminium alloy forms an oxide layer when exposed to air. The microstructure of this alloy plays a critical role in determining its mechanical behavior. This study utilized aluminum alloy A356, composed of 92.05% aluminum, 7% silicon, 0.35% magnesium, 0.20% copper, 0.10% manganese, and 0.10% zinc. This alloy exhibits extremely high corrosion resistance, similar to stainless steel, with a melting point of 650°C. The study examines multi- component (mainly Al with Si) A356 containing small amounts of Mg, Cu, Mn, and Zn for their complex microstructural behavior. It includes observations using techniques such as optical microscopy and X-ray diffraction (XRD). This research was carried out to investigate different areas of the same metal’s microstructure and to discover the influence of cooling rates during the solidification process. The findings revealed that there are dissimilarities between the central parts and outer areas, as well as similarities between the two side portions. Also, this study highlights processing conditions’ impact on the material response while looking at heat transfer rate effects during solid-state transformation. The findings of this study highlight the presence of distinct microstructures (dendritic and equiaxed structures) across different sections of the cast Aluminum alloy A356. These findings contribute to a better understanding of the microstructure-property relationship of Aluminum alloy A356, assisting in improvising design and manufacturing processes for enhanced performance.

Abstract: The A356 Aluminium Silicon alloy is reinforced with Silica Carbide particles (SiCp) to form metal matrix composite by stir casting method to study the hardness and wear properties. The composites are prepared for weight fraction of 2, 4 and 6% of SiC with the base alloy and their characteristics are observed at post T6 full heat treated condition. The optical microscopic metallography observation shows the rosettes of uniform spheroidal grains of strain free eutectic silicon phase in proeutectic Aluminium matrix after heat treatment. The hardness and wear properties of the A356-SiC composites have increased with the increase in weight percentage of reinforcement particle in the base alloy. Maximum hardness and wear resistance is observed for 6% SiC which is the maximum percentage of inclusion of secondary element considered under this study. A comprehensive discussion is made on the strengthening of the A356 alloy on addition of hard SiC particles that has improved the hardness and wear characteristics of composites in heat treated conditions.

Abstract: In this study, the structures of Al-5Ti-1B master alloy and its influence on microstructures and mechanical properties of A356 alloy were investigated. The results show that Al-5Ti-1B master alloy consisted of the uniform distribution of lump-like TiB₂ and network of TiAl₃ on α-Al matrix. The addition of the Al-5Ti-1B master alloy can significantly reduce the grain size of A356 alloy. The mechanical properties of A356 alloy, i.e. ultimate tensile strength, yield strength and elongation were also improved. The use of Al-5Ti-1B master alloy as a grain refiner in the casting process of A356 alloy can effectively enhance the grain refinement and thus improve the mechanical performance of A356 alloy.

Abstract: A three phase electromagnetic stirrer was used to agitate aluminum A356 slurry and a dry and oxygen free argon gas was introduced in to the slurry by a porous graphite core at a same time. The prepared semi-solid slurry was then transferred into a metallic mold and was compacted by a drop weight. Results demonstrated a favorable increase in shape factor, decrease in aspect ratio and average diameter size at different intensities of stirring. The intensity of stirring was changed by altering the current passed through the magnetic coil and also bubbling intensity via the porous graphite diffuser. Different time intervals for electromagnetic stirring and gas induction were applied. Agitating the slurry for 90 Sec. separately by electromagnetic stirrer and GISS method, gave better results in terms of shape factor, decrease in average diameter of the globules and aspect ratio.

Abstract: Semi-solid squeeze casting (SS-SC) is a new processing technology which combines semi-solid processing (SSP) and squeeze casting (SC). In this process, semi-solid slurry fills mold by using its rheological property and solidifies under high pressure. It has several advantages, such as stable filling, small heat impact to the mold, low cost, high density and excellent mechanical properties of castings, which receives more and more attention. The microstructure of castings provided by SS-SC is quite different from that of casting provided by conventional SC in as-cast condition, which leads to differences in the evolution of microstructure and mechanical properties in heat treatment process. In this study, A356.2 aluminum alloys castings were provided by both SS-SC and conventional SC respectively. The evolution of microstructure and mechanical properties of castings during heat treatment was investigated to obtain the best mechanical properties of semi-solid squeeze castings. Keywords:Microstructure, Mechanical properties, Heat treatment, A356 alloy, Semi-Solid Squeeze Casting

Abstract: The TiN-Al composite coatings on A356 alloy were successfully synthesized by mechanical alloying (MA) of Al, TiN and C powders under argon atmosphere. Meanwhile, the optimal parameters for mechanical milling processing were determined by changing the material ratio (Al: TiN: C), milling time and the ball-to-powder weight ratio, which might have a significant improvement on the wear resistance of A356 alloys. The microstructures and mechanical properties of A356 alloy samples with TiN-Al composite coatings were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and Brinell hardness test. It was found that under the optimal conditions, i.e. the material ratio of (Al: TiN: C= 17.5:1.5:1), the ball-to-powder weight ratio of 14:1 and the milling duration of 12 h, the Brinell hardness of sample-6 could be remarkably increased to 143.80 HBW. With the TiN-Al coatings fabricated by MA process, the mechanical properties of aluminum alloys could be significantly improved.

Abstract: A356 alloy was refined with a new master alloy of Al-5Ti-B-10Sr. The microstructure and mechanical properties of the refined A356 alloy with different content of master alloy (0, 0.1, 0.3, 0.5 and 0.7 wt.%) were investigated. The results show that the refining effect becomes stronger as the master alloy content increasing from 0.1 to 0.3 wt.%, and then shows slight decrement until 0.7 wt.%. An optimal combination of the tensile strength (193 MPa) and the elongation (17.8%) of as-cast A356 alloy was achieved with 0.3 wt.% of refining master alloy. Compared to the non-modified A356 alloy, the tensile strength and the elongation were improved by 10% and 242%, respectively.

Abstract: The study investigates the application of centrifugal casting process in the production of a complex shape component, Pelton turbine bucket. The bucket materials examined were functionally graded aluminium A356 alloy and A356-10%SiC_p composite. A permanent mould for the casting of the bucket was designed with a Solidworks software and fabricated by the combination of CNC machining and welding. Oil hardening non-shrinking die steel (OHNS) was chosen for the mould material. The OHNS was heat treated and a hardness of 432 BHN was obtained. The mould was put into use, the buckets of A356 Alloy and A356-10%SiCp composite were cast, cut and machined into specimens. Some of the specimens were given T6 heat treatment and the specimens were prepared according to the designed investigations. The micrographs of A356-10%SiC_p composite shows more concentration of SiC_p particles at the inner periphery of the bucket. The maximum hardness of As-Cast A356 and A356-10%SiC_p composite were 60 BRN and 95BRN respectively, recorded at the inner periphery of the bucket. And these values appreciated to 98BRN and 122BRN for A356 alloy and A356-10%SiC_p composite respectively after heat treatment. The prediction curves of the ultimate tensile stress and yield tensile stress show the same trend as the hardness curves.

Abstract: In this paper, the castings of A356 alloy were made by the rheo-squeeze casting with slurry-making from the process of LSPSF. Experiments were designed to study the influence of three parameters in rheo-squeeze casting process, such as injection speed, mould preheating temperature and injection pressure, on castings performance. The results show that high-quality castings were produced with the injection speed of 0.5m/s ,the mould preheating temperature of 240°C, the injection pressure of 50MPa. The mechanical properties, such as the yield strength, tensile strength and elongation of the castings with T6 heat treatment are 241 MPa, 328MPa and 11.6%, respectively.

Abstract: Automobile wheel of A356 alloy was cast by low pressure casting process. The effect of heat treatment process on microstructures and mechanical properties of A356 alloy cast was discussed. The results indicated that optimal parameters of heat treatment process for A356 alloy included solution temperature of 535°Cand holding time of 4.5hours, aging temperature of 145°Cand holding time of 4hours. Ultimate strength of A356 is 270MPa and elongation rate is 10%. Meanwhile, the microstructure has been apparently improved. The eutectic silicon particle became more spheroidal and distributed uniformly in matrix.