Ab initio identified design principles of solid-solution strengthening in Al

Sci Technol Adv Mater. 2013 Mar 21;14(2):025001. doi: 10.1088/1468-6996/14/2/025001. eCollection 2013 Apr.


Solid-solution strengthening in six Al-X binary systems is investigated using first-principle methods. The volumetric mismatch parameter and the solubility enthalpy per solute were calculated. We derive three rules for designing solid-solution strengthened alloys: (i) the solubility enthalpy per solute is related to the volumetric mismatch by a power law; (ii) for each annealing temperature, there exists an optimal solute-volume mismatch to achieve maximum strength; and (iii) the strengthening potential of high volumetric mismatch solutes is severely limited by their low solubility. Our results thus show that the thermodynamic properties of the system (here Al-X alloys) set clear upper bounds to the achievable strengthening effects owing to the reduced solubility with increasing volume mismatch.

Keywords: 10.07; 30.05; 30.06; Al alloys; DFT; ab initio; alloy design; solid-solution strengthening; solubility.