The influence of cooling rate (1.5, 0.3 and 0.1 °C/s) on the hot tearing susceptibility (HTS) of Mg-9Al-1Zn-0.8Ce alloy was investigated by taking advantage of numerical simulation and experimental methods. Filling and solidification processes were observed directly using AnyCasting software. The results demonstrated that the reduction of cooling rate increases the residual melt modulus, deteriorate strain and stress concentration at last stage of solidification, and decrease the hot tearing resistance of alloy finally. The maximum value of HTS was obtained at the average cooling rate of 0.1 °C/s owing to the coarse microstructures and bulk Al11Ce3. The minimum value of HTS appeared at the rate of 1.5 °C/s thanks to the finest microstructures and a large amount of eutectic. With the increase of cooling rate, hot tearing susceptibility of the alloy shows a rapid reduction at beginning, and a slow decline followed. Besides, morphology of fracture surface and distribution of secondary phase were further discussed.

In this paper, the Back-Propagation neural network (BP network) and the establishment of the AZ61 magnesium alloy high temperature constitutive model and test data obtained for training the neural network, after training the neural network to become a knowledge-based constitutive model formed AZ61 magnesium alloy flow stress and dynamic recrystallization of the neural network model tested by the neural network model with traditional regression methods predict contrast, results showed that the higher the accuracy of the neural network model for dealing with a large number of test data to establish the constitutive relations of materials with high stress and promotion of value.

The microstructure and mechanical responses of the AZ31 with the addition of 1.8% Sn alloys have been studied and compared. Mg alloy sheets were prepared with metal model casting method and subsequent processes by conventional extrusion (CE) and differential speed extrusion (DSE). Mg alloys were hot extruded at 400oC with the extrusion ratio of 101:1. The microstructure of Mg alloy sheets was examined by optical microscopy (OM) and scanning electron microscope (SEM). The results indicated that the grains were dynamically recrystallized after the extrusion process. Moreover, DSE process dramatically enhanced the room temperature ductility of the extruded sheets. It was also presented that the Mg alloy processed by DSE exhibite a classical dimple structure as a result of slip accumulation and ductile tear.

The two-stage deformation was processed to ZM21alloy as cast at different parameter condition, and structure evolution and mechanical property was analyzed. The results indicate that the grain of ZM21 alloy as cast will be fined by the two-stage extrusion deformation, and its size can decreases from about 100μm to 15.6μm. The strength of ZM21 alloy can be raised by the two-stage deformation, up to 261.7MPa, At the same time, the prolongation rate is more than 16% by the two-stage deformation.

Hot compression tests of AZ61 magnesium alloy were performed on gleeble1500D at strain rate ranged in 0.01~1s-1 and deformation temperature 350~400°C.The results show that the flow stress and microstructures strongly depend on the deformation temperature and the strain rate. When the temperature was reduced and the strain rate was enhanced, the area after dynamic recrystallization was enhanced, and the average dynamically recrystallied grain size reduce. But the dynamically recrystallied grain size was not well-proportioned. In this paper the 350°C×1s-1 was suggested.