Thermodynamic Modeling Of The Sn-Hf, Sn-Y, Sc-Zn,Al-Li-Mn And Al-Cu-Li Systems In Al Alloys

CALPHAD(CALculation of PHAse Diagram) technology has been successfully used in the field of phase diagram calculation of multi-component materials. The core of CALPHAD technology is the use of reasonable thermodynamic model and accurate thermodynamic data. The important Al-based alloy systems such as Sn-Hf, Sn-Y, Sc-Zn, Al-Li-Mn and Al-Cu-Li were selected for the CALPHAD calculation in the present work. The research contents are as follows:1. The enthalpies of formation at0K for HfSn2, HfSn, Hf5Sn4, Hf5Sn3, ScZn, ScZn2, Sc17Zn58, Sc3Zn17and ScZn12were calculated by first-principles calculations.2. Based on the critical assessment of the available experimental data in the literature for the Sn-Hf, Sn-Y and Sc-Zn binary systems, the thermodynamic models for the individual phases in each system were established. The thermodynamic parameters of the Sn-Hf、Sn-Y and Sc-Zn systems were obtained by the thermodynamic optimization calculation. The obtained thermodynamic parameters can not only describe the phase diagrams of the Sn-Hf, Sn-Y and Sc-Zn systems, but also be extrapolated to the ternary or higher-order diagrams, which is beneficial to understand the alloying behaviors and the microstructures’ influence of the additive elements such as Sc and Sn in the Al alloys. The obtained thermodynamic parameters for these binary systems have been incorporated in the most complete thermodynamic database of A1alloys in the world.3. Based on the parameters of the boundary binary systems in the database of the A1alloys of our research group, the thermodynamic parameters of the Al-Li-Mn and Al-Cu-Li ternary systems were optimized. The obtained parameters in this work can well describe the Al-Li-Mn and Al-Cu-Li ternary systems, and have a good compatibility with the thermodynamics database of our research group.