Control of Amount of α-Al Phase Particles in near Eutectic Al-Si Alloy by Electromagnetic Stirring

Al-Si alloy is widely used as a casting alloy. The α-Al phase in the semi-solid state has low Si content in the Al-Si alloy. Then by separation of these α-Al phases from semi-solid Al-Si alloy, refining of aluminum can be possible. But, in near eutectic Al-Si alloy, few primary α-Al phases can be crystallized. If the fraction ratio of the α-Al phase can be increased, near eutectic Al-Si alloy can refine, and this method can be used for recycling. In this study, the effect of electromagnetic stirring (EMS) on the microstructure, especially the amount of the α-Al phase particles was investigated. A rotational magnetic field was applied to JIS ADC12 alloy which has near eutectic content during slow cooling from the liquid state to the solid-state, by using a three-phase AC coil. By applying EMS at solidification, the shape of the α-Al phase became particle shape from dendrite shape, and the amount of α-Al phase particles was increased. Moreover, by applying unidirectional intermittent EMS, the volume fraction of α-Al phase particles was decreased with increasing intermittent applying time. In ADC12 alloy, the primary α-Al phases can be crystallized only 10% generally, but it could be obtained over 40% by applying EMS. This means that the semi-solid slurry of near eutectic alloy with over 40% of fraction solid can be obtained by applying EMS.

RAFFMETAL EN AB-Al Si7Mg0.6 (EN AB-42200)

Raffmetal EN AB-Al Si7Mg0.6 (EN AB-42200) is a heat-treatable, Al-Si-Mg casting alloy in ingot form for remelting. It is used extensively for producing sand, permanent mold, and investment castings for applications requiring a combination of excellent casting characteristics, high strength with good elongation, and good corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-483. Producer or source: Raffmetal S.p.A.

Effect of Short Solution Heat Treatment Time on the Microstructure and Properties of Al-Si-Mg-Cu Alloys

In this work, a solution heat treatment of Al-Si-Mg-Cu casting alloy was analyzed. A new short solution heat treatment (SHT) with only 60 min has been allowed. The results revealed that this short SHT enables the improvement of the dendritic structure and the spheroidization of the eutectic silicon particles. Furthermore, the alloy showed improved mechanical properties when compared to the same alloy subjected to a longer SHT of 4 h. It was observed that increasing the SHT temperature can accelerate the dissolution and homogenization of the silicon particles and intermetallic precipitates in the matrix.