Aluminum And Zinc Alloy Elements On Magnesium Alloy Stability Of Mesophase The First Principles Of The Research

First principles calculations were carried out to study electronic structure, mechanical properties of Al2Mg three laves phase which found in AZ series alloys, makes a further discussion of thermodynamic stability on these three laves phase, obtained optimum-doping elements and the composition ratio by doping simulating, then prepared Mg-Al-Zn alloy, Analysis precipitation kinetics and mechanical properties of the alloy, finally, determined structural changes in the aging precipitation process and precipitation relationship with the matrix phase by transmission electron microscopy and spectroscopy experiments, explore the aging precipitation process at different temperatures, different aging time on the precipitation kinetics, then explain the formation process of transition phase on the electron-atom level.Calculate charge density maps of C14, C15, C36by Simulation, you can see the form and strength of the interactions between atoms visually. Al-Al is the parity of covalent bonding, Mg-Al is ionic bonding, Mg-Mg is metal bonding. The bond energy strength of the order were:covalent bond>ionic bond>metallic bond, comparison on enthalpy of formation, cohesive energy and electronic structure of the three laves phase, found that the phase stability of the order is:C14> C15> C36.Doped alloying elements in C14structure which is the most stable by simulation, alloying elements were Ca、Ni、Cu、Sr、Pd、Ag、Cd、Sn、Zr、Ba、Pt、Au、Hg、 Ir, C14unit cellstructure has12atoms, chemical formula Al8Mg4. These alloying elements and Al2Mg forms substitution solid solution in the modeling, doping replacement Mg or Al atoms in the unit cell location, replacement chemical formula are Al8Mg3X, Al7Mg4X (X=Ca、Ni、Cu、Sr、Pd、Ag、Cd、Sn、Zr、Ba、Pt、Au、Hg、Ir), compare these14kinds of the structural stability of the structural model, after the geometry optimization and energy calculation, the enthalpy of formation, combined with unit cell shows that:the alloy has better thermodynamic stability when the alloying elements Cu and Ni.Melting preparation in accordance with the calculated alloying elements and the composition ratio, wire cutting the sample for the φ20mm×10mm, solution treatment temperature is420℃, followed by a3min-1080min aging treatment, test conductivity and hardness, Analysis precipitation kinetics and mechanical properties of the alloy...