Semi-solid Aluminum Alloy Slurry Research Articles

Preparation of semi-solid aluminum alloy slurry poured through a water-cooled serpentine channel

A water-cooled serpentine channel pouring process was invented to produce semi-solid A356 aluminum alloy slurry for rheocasting, and the effects of pouring temperature and circulating cooling water flux on the microstructure of the slurry were investigated. The results show that at the pouring temperature of 640–680°C and the circulating cooling water flux of 0.9 m3/h, the semi-solid A356 aluminum alloy slurry with spherical primary α(Al) grains can be obtained, whose shape factors are between 0.78 and 0.86 and the grain diameter can reach 48–68 μm. When the pouring temperatures are at 660–680°C, only a very thin solidified shell remains inside the serpentine channel and can be removed easily. When the serpentine channel is cooled with circulating water, the microstructure of the semi-solid slurry can be improved, and the serpentine channel is quickly cooled to room temperature after the completion of one pouring. In terms of the productivity of the special equipment, the water-cooled serpentine channel is economical and efficient.

Preparation and Rheocasting of Semi-solid Aluminum-alloy Slurry with Indirect Ultrasonic Vibration Process

ABSTRACTDirect ultrasonic vibration (DUV) method by dipping the horn into the melt can be used to make semi-solid metal slurry, but application of this process is embarrassed because of the erosion problem of titanium-alloy horn by aluminum melt. In order to avoid this problem, a slurry-making process with indirect ultrasonic vibration (IUV), in which the horn is vibrated under the outside of the metallic cup containing alloy melt, has been developed in this research. Semisolid slurry of A356 Al alloy was prepared by this process, and the effects of IUV treatment time on the morphology of the primary α-Al phase and mechanical properties of rheo-diecasting samples were studied. The results indicate that excellent semisolid slurry of A356 Al alloy could be obtained within 50s by applying IUV near its liquidus temperature, and the average diameter and shape coefficient of the primary α-Al particles were 75μm and 0.62, respectively. IUV treatment time had a significant effect on the mechanical properties of the rheo-diecasting samples, and samples treated by IUV for 50s had the maximum tensile strength and elongation. The maximum as-cast tensile strength and elongation were 244MPa and 7.5% respectively, which were increased by 10% and 75% respectively compared to conventional molten-melt die-casting samples. In addition, the mechanism of preparing semisolid slurry of A356 Al alloy by IUV is discussed.

Numerical Simulation of Die Casting for Semi-Solid Aluminium Alloy and its Mould Research

With consideration of the viscosity of semi-solid aluminum alloy slurry and the mold filling characteristics in die casting, the die-casting mould for semi-solid aluminum alloy has been designed and manufactured on the basis of the standard samples. The process of mold filling and solidification of semi-solid aluminum alloy in die casting was simulated by using ProCAST software. With combination of simulation results with die casting experimental data, the results indicate that the influence of heating system of the mould and cross section of ingate for the mould on flowing of semi-solid aluminum alloy in mould cavity is important in this work.