The Development and Validation of New Thermodynamic and Mobility Databases for Aluminum Alloys

CALPHAD based tools are an integral component of ICME in terms of predicting the underlying thermodynamics of multicomponent alloys of industrial importance, the phases formed , their sensitivity to compositional variation and temperature, phase transformations, soldification behavior  and microstructure evolution. Such tools are useful both from an alloy design perspective while also improving understanding of existing alloys, and process optimization.

The CALPHAD approach relies on the capability to provide fundamental phase equilibrium and phase transformation information, which is possible due to the adopted methodology where free energy or atomic mobility of each phase in a multicomponent system is modeled hierarchically from lower-order systems, and model parameters are evaluated by considering ab-initio and various experimental data.

For more than fifteen years CALPHAD has been applied successfully within the aluminium industry, but to maximize the benefits of ICME requires further development of both software and databases; databases which cover broader ranges of composition for example. With ongoing research and development into new aluminum alloys for the aerospace market, with the drive towards lower density, higher performance alloys, databases need to be developed which take these requirements into account.

Presented here is a new thermodynamic database, and a corresponding mobility database for Al- alloys based on the critical evaluation of all the constituent binary systems across their full range of composition, 59 ternaries, 15 quaternaries and 1 quinary.   This database contains all the important Al- alloy phases within a 26-element framework [Al-Cu-Fe-Mg-Mn-Ni-Si-Zn-B-C-Cr-Ge-Sn-Sr-Ti-V-Zr-Ag-Ca-H-Hf-K-La-Li-Na-Sc] and in total 345 solution and intermetallic phases are included