Why is there no “Moore’s Law” for the creation of stronger and more durable metals? Because there is a unique complexity to mechanical properties of metals: the strength, hardening, embrittlement, fracture, and fatigue are controlled by multi-defect interactions (dislocations/solutes/precipitates/grain boundaries). However, such multi-defect interactions are beyond the scope of analytical elasticity theory, and thus require a deeper inquiry at atomistic and quantum scales. And observed macroscopic mechanical behaviour arises from the collective interactions among such defects over large length and time scales. The PI will tackle the fundamental challenge of the multi-defect, multi-scale problem in metal alloys through a combined theory/simulation effort that will push forward the frontiers of computational metallurgy and yield new, quantitative, predictive models of the mechanical performance of metals alloys that will accelerate metal design. Three specific thrusts are proposed to predict the role of solute chemistry on : (i) fundamental dislocation phenomena, and the resulting effects on plastic flow and ductility (Solute/Dislocation/Dislocation interactions); (ii) dislocation transmission/absorption and damage nucleation along boundaries (Solute/Grain-boundary/Dislocation interactions); and (iii) the propagation of cracks under monotonic and fatigue loading (Solute/Crack/Dislocation/Grain-boundary interactions). Small-scale Quantum, Atomistic, and/or Dislocation-level simulations will be designed to probe mechanistic concepts and to validate new predictive theories and new material constitutive models. This approach is now feasible due to new multiscale modeling techniques developed by the PI and his recent quantitative models that resolve long-standing problems in metallurgy. The theories and models emerging from this research will allow for generalization of the mechanisms across metals, and will enable the enhancement and design of new metal alloys.