The Intelligent Design of High Strength, Creep-Resistant Aluminum Alloys

This paper describes a practical approach to the design of improved age-hardenable aluminum alloys for moderate temperature application. The process involves extensive empirical research with quantitative analytical techniques, theoretical simulation and modeling, and computational thermodynamics. Microstructure characterization and analytical transmission electron microscopy (TEM) are being employed to refine the development of the quaternary Al-Cu-Mg-Ag phase diagram. Differential scanning calorimetry (DSC) and electron diffraction are being implemented to investigate the microstructural evolution of the ternary alloys and to validate calculated equilibrium phase boundaries. Energy dispersive spectroscopy (EDS) is also being used to illustrate the effect of trace additions on the phase boundaries that are of paramount consideration for the thermal stability of this class of alloys. Computer simulation and modeling are being used to identify the microstructure that will result in the optimal combination of mechanical properties. Unavailable parameters will be calculated from first principle atomistic modeling. Once identified, the desired microstructure can be manipulated through various thermo-mechanical processing techniques in order to achieve the prescribed microstructure. This approach should prove as an example of streamlined alloy design and therefore aid in the early insertion of new high performance materials. (Example: Al-Cu alloys.)