Al-zr-m (m = Dy, Cu And Mg) Alloy Phase Diagram Study

Due to their excellent performance such as high specific strength, good corrosion resistance, etc., aluminum alloys can be widely used in various fields, including aerospace. The design of new high-strength aluminum alloys is always a hot topic for international material community and the field of industry. Metals, like zirconium, copper and magnesium can improve the properties of aluminum alloys from many aspects. The additive of rare earth into aluminum alloys can refine grain, prevent segregation, eliminate gas and impurity, and ameliorate structure, then improve their mechanical performances, physical and processing properties. In order to design new high-strength aluminum alloys, selecting the appropriate alloying elements and deciding their composition is a critical step. Phase diagram for those relevant systems will provide very important guidance on the choice of those alloying elements and their compositions.Supporting by the National Natural Science Foundation of China (No.50971136), "Phase Diagram and Alloying on Heat-Resistant Cast Aluminum Alloys", some Aluminum-Zirconium alloy systems have been studied through experimental determination and thermodynamic calculation in this paper. The main work is as follows:1. By using XRD, SEM/EDX measurement, the phase relations of the Al-Dy-Zr ternary system at 773K have been determined. The 773K isothermal section consists of 17 single-phase regions,32 two-phase regions and 16 three-phase regions. The existence of the ternary compound Al30Dy7Zr3 has been confirmed.2. By Rietveld method, the crystal structure of the compound AlDy2 has been refined.3. Part of the Al-Cu-Zr ternary system's phase relations at 773 K have been determined by using XRD, SEM/EDX measurement.4. The phase relations of Al-Mg-Zr ternary system of magnesium-rich corner at 673K have been determined.