| Due to hexagonal close-packed structure of magnesium alloys and their relatively poor workability, the main fabrication route of magnesium alloy parts remains die-casting, and the development of wrought magnesium alloys are relatively slow. Wrought magnesium alloys have higher strength and toughness, and can be made more diverse products to meet different conditions. So it is necessary to investigate wrought magnesium alloys with high strength and tougness. In this paper the focus of investigation is strengthening and toughening of wrought magnesium alloys, and finding a new method to produce high performance wrought magnesium alloys.In this paper, three typical wrought magnesium alloys, AZ31, AZ61 and ZK60 are choosed as the base alloys, the technology of microalloying, electromagnetic continuous casting (EMC), hot extrusion, aging treatment and electromagnetic-suspension forming is employed. The microstructure and mechanical properties are investigated by MEF-4A Metallographic Microscope, XRD-6000 diffractometer, JSM-5600LV Scanning Electron Microscope, EPMA-1600 Electron Probe microanalyser, TG220S-Twin JEM-100CXII Transmission Electron Microscope, HB-3000-1 Brinell Hardness Tester and MTS NEW-810 Materias Test System, and the mechanism of strengthening and toughening is explored. calculated. A 3-D mathematical model of the electromagnetic suspension continuous casting casting process for AZ31 round billet has been developed using the finite differential method (FDM).The results of the study are showed bellow:An optimized EMC technical parameters has been obtained after many experiment. The billets with EMC and microalloying have smooth surface, and the defects, such as segregation, trapped oxide on the billet surface can be eliminated. The refined grains andβ-Mg17Al12 phases with small size are observed. The electromagnetic field and microalloying can improve the mechanical properties of wrought magnesium alloys. The EMC of ZK60 magnesium alloy casting with different electromagnetic powers are investigated, the results show that the best refined grains and combination property are obtained when the electromagnetic power was 10 kW.The electromagnetic suspension casting and electromagnetic suspension continuous casting system are designed, and experiments for wrought magnesium alloys are carried out by the systems. The complex suspension particles easily adding non-metal particles are produced, the wettability between the non-metal particles and melting metal is improved. The electromagnetic suspension casting with magnesium powder and complex suspension particles can both impoved the microstructures of wrought magnesium alloys, properties are increased by simple suspension particles, UTS (Ultimate tensile strength) of magnesium alloy is improved by complex suspension particles, but the Elongation is decreased. The electromagnetic suspension continuous casting for AZ31 magnesium alloy is investigated by ZrB2/AZ31 complex suspension particles, the results show that the microstuctures are improved, and the refined grains from the boundary to the center of the billet.The mathematical model of the electromagnetic continuous casting process was utilized to predict the temperature in the billet of electromagnetic suspension continuous casting, after some thermophysical properties were processed. The model had been validated by comparing the calculated temperature profiles with the measured temperature profiles. The effect of amount of suspension particles on temperature field in the billet was studied. The conclusion was drawn that initial temperature of the alloy drops, solidification time of billet shortens, heat-transfer capability declines, comprehensive cooling ability enhances, solidification shell thickness increases, sump depth decreases, initial position of solidification shell enhances and slope gradient of sump profile decreases with increasing the amount of suspension particles.Hot extrusion of AZ31X, AZ61X and AZ61XE magnesium alloys are investigated, the results show that the microstructures of as-extruded magnesium alloys are made of 3-15μm fine homogeneous grains due to DRX (Dynamic recrystallization), and the UTS, Hardness and Elongation are improved greatly. Discontinuous precipitation occurs for AZ31X magnesium alloy after aging heat treatment, but the microstructures of AZ61X and AZ61XE are form of discontinuous precipitation phase on the grain boundary and continuous precipitation phase in the grains. The aging heat effect of AZ61X and AZ61XE magnesium alloys are better than that of AZ31X magnesium alloy.
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