We have developed a general theoretical framework for solute strengthening in metals to predict the dependence of the initial plastic yield stress as a function of the temperature, strain-rate, and solute types and concentrations.
The important feature of the model is that strengthening depends on favorable statistically-occurring arrangements (spatial fluctuations) of the solute atoms, and the relevant spatial fluctuations are determined self-consistently.
The model uses quantum calculations of the solute/dislocation interaction energies as input, and has no fitting parameters. The model was first applied to Al-X alloys for various solutes X, and subsequently extended to basal slip in Mg and then solute strengthening of twinning in Mg. We are now applying extensions of the model to understand arbitrary random solute systems and in particular High Entropy Alloys. Aspects of the model have been examined more generally, and compared with some traditional textbook models.
Key publications:
- G. P. Leyson, W. A. Curtin, L. G. Hector Jr., and C. Woodward, “Quantitative prediction of solute strengthening in aluminium alloys”, Nature Materials 9, 750-755 (2010).
- G. Leyson, L. G. Hector, and W. A. Curtin, “Solute strengthening from first principles and application to aluminum alloys”, Acta Mater. 60, 3873-3884 (2012).
- G. P. M. Leyson, L. G. Hector, and W. A. Curtin, “First-Principles prediction of yield stress for basal slip in Mg-Al alloys”, Acta Mater. 60, 5197-5203 (2012).
- M. Ghazisaeidi, L. G. Hector Jr., and W. A. Curtin, Solute strengthening of twinning in Mg, Acta Mater. (2014).
Additional work:
- D. Olmsted, W. A. Curtin, and L. G. Hector, “Molecular Dynamics Study of Solute Strengthening in Al/Mg”, J. Mech. Phys. Solids 54, 1763-1788(2006).
- W. A. Curtin, “New interpretation of the Haasen plot in solute-strengthened metal alloys”, Scripta Mater. 63, 917-920 (2010).
- G. Leyson and W. A. Curtin, “Friedel vs. Labusch models for solute strengthening”, Acta Mater. (2013)
- G. P. Leyson and W. A. Curtin, Solute strengthening at high temperatures, in preparation.