Ab-initio guided design of TRIP/TWIP titanium alloys for enhanced yield strength

New TRIP/TWIP strengthening parameters quantifying the influence of alloying elements on the yield strength have been determined through considering the elementary energy barrier associated with stress-induced martensitic transformation and 332 twinning, respectively. Ab initio calculations have been performed and linked with solute concentration, average electron-to-atom ratio e/a and electronic Bo-Md parameters for a set of classical b-stabilizer elements. It is found that the e/a value governs the critical energy activating TRIP/TWIP effects; however, this correlation is not universal—high period elements can further increase transformation barriers even at comparable or lower e/a. The presented results and first-principles framework act as a novel tool supporting design of the new alloys with controlled yield strength.