PREDICTING MG STRENGTH FROM FIRST-PRINCIPLES: SOLID-SOLUTION STRENGTHENING, SOFTENING, AND CROSS-SLIP

摘要

Predictive modeling of strength from first-principles electronicstructure methods offers great promise to inform Mgalloy design. Simulating the mechanical behavior for newalloys requires an understanding of mechanisms for deformationat atomic-length scales, with accurate chemistry, extendedto larger length- and time-scales. To design ductileMg alloys, we identify solutes that strengthen basal slip andincrease cross-slip. First-principles modeling of dislocationsspredict dislocations motion under stress through a field of solutesat a finite temperature. First-principles flexible boundaryconditions compute accurate core structures of basal andprismatic dislocationss, and dislocations/solute interactions.We develop new models to predict the solute-strengtheningfor basal dislocationss; cross-slip from basal- to prismatic-slipfor α-type screw dislocationss; and cross-slip stress with solutes.First-principles data provides insight into the responseof dislocationss to solutes and quantitative data to build newpredictive models.