The microstructure and mechanical properties of 7050 alloy rheo-castings after treated by Annular Electromagnetic Stirring (A-EMS) melt treatment were investigated. The results revealed that, under A-EMS, the refinement and homogeneity of the solidification structure could be improved greatly and the slurry was suitable for the following rheo-casting; and also the hot-cracking defects in the casting process were significantly alleviated, meanwhile, the strength and ductility of the alloy casting were found to be comparable to those of conventionally forged 7000 series alloys.

The application of Annular Electromagnetic Stirring (A-EMS) for production of high-quality slurry has been examined. Al-11%Zn-3%Mg-1%Cu-0.13%Zr alloy was used to investigate the effect of A-EMS at various temperatures above liquidus on structure refinement. The results indicate that the grain size was reduced greatly and the homogeneous structure was achieved. Instead of the case in tradition, the nucleation particles gradually formed and the enhanced grain refining efficiency can be mainly attributed to an instantaneous nucleation of numerous heterogeneous nucleation of Al3Zr in the superheating melt under A-EMS.

The Φ730 / Φ340 mm hollow ingots of 2A14 aluminium alloy were produced by conventional and electromagnetic stirring (EMS) DC casting with extremely fine grain morphology. The results indicate that the metallographic microstructure of the alloy was more uniform and homogeneous in the EMS hollow ingot and the finer grain size was obtained. The average grain size dramatically decreased from 115 μm to 70 μm with applying EMS. The macrosegregation patterns of Cu element in EMS and conventional hollow ingots along the radial direction were both following the similar trend that positive segregation occurred in inner subsurface and middle section. Meanwhile negative segregation occurred in section offset to inside of centerline and outer surface. The extent of macrosegregation in EMS hollow ingot was severer than that in the conventional one. The mechanism of EMS was discussed to reveal its effect on the microstructure and macrosegregation.

High-strength aluminum alloy with large-scale and thin-walled complex castings have broad application prospects in aerospace, weapons, electronics, defense and military industries. However, due to the uneven thickness of the plate, the casting defects are inevitable by the ordinary casting method, and it is impossible to accurately control the shape and performance of the casting in the casting process. Previous studies have found that the semi-solid rheological extrusion casting technology with short process and near-end type can help solve this technical problem. Therefore, this paper studies the semi-solid rheological extrusion casting process of thin-walled complex casting of ZL114A aluminum alloy. The combination of numerical simulation and experimental research is used to simulate and optimize the filling and solidification process of thin-walled specimens. Based on this, a semi-solid rheological extrusion casting test was conducted. The result showed that, (1) The optimized model can well reflect the filling and solidification process under different rheological extrusion casting parameters, and obtain defect-free castings through process optimization. (2) The thin-walled parts of the thin plate casting produced by semi-solid rheology extrusion have excellent mechanical property and ductility.