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The microstructure and mechanical properties of the 7085 ingot casting was tested by OM, SEM and EDS, the fatigue damage was observed in the driving test process, the temperature gradient distribution was adjusted observably by using the FEM simulation analysis. By adjusting the pouring temperature, many micro shrinkage metallurgical defects were eliminated, the tensile strength, yield strength and elongation were raised to 498MPa, 362MPa and 7.4% at the T6 heat treatment state.

The effect of the second-stage aging process on the tensile properties, fracture toughness and electrical conductivity of 7050 aluminum alloy die forgings was studied, and the mechanism of strengthening and toughening was analyzed by transmission electron microscope and scanning electron microscope. The results show that with the extension of the second-stage aging time, the morphology of the precipitation phase remains unchanged, but the average radius of the precipitation phase and the distance between each other gradually increase. The fracture modes at this aging temperature are mixed fracture mechanisms of dimple fracture and intergranular fracture, and the number of dimple fractures increases with time. With the extension of the second-stage aging time, the strength of the alloy decreases, and the fracture toughness and stress corrosion resistance increase. The alloys heat-treated at 120°C×6 h +177°C×6~8 h two-stage aging process have excellent comprehensive properties.

Nearly monodispersive CaF2hollow microspheres were synthesized by a facile aqueous solution route from the mixed aqueous solutions of CaCl2, Na2WO4, and NaF at room temperature. The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy, and N2adsorption-desorption techniques. The CaF2hollow microspheres have an average diameter of about 1.5 µm and a hollow interior of 0.5 µm. The shell is composed of numerous single-crystalline nanoparticles with diameter of about 20 nm. The morphologies and diameters of the CaF2products are strongly dependent on the experimental parameters, such as the concentration of the aqueous NaF solution and the reaction temperature. The synthetic experiments indicate that the growth process of CaF2hollow microspheres involves first the formation of CaWO4solid microspheres and then the formation of CaF2solid microspheres through the reaction between CaWO4and F-ions controlled by the difference of the solubility product for CaWO4and CaF2. Phenomenological elucidation based on TEM observations and XRD patterns of intermediate products at different precipitation stages indicates that the formation mechanism for the CaF2hollow microspheres is related to the Ostwald ripening mechanism. N2adsorption-desorption measurement shows that the CaF2hollow microspheres possess a high Brunauer-Emmett-Teller surface area and porosity properties. The synthetic procedure is straightforward and represents a new example of the Ostwald ripening mechanism for the formation of inorganic hollow structures in an aqueous solution at room temperature.