267933 On the Chemistry of Deformation: Theory of Solute Strengthening in Aluminum and Magnesium Alloys

Tuesday, October 30, 2012: 12:30 PM
415 (Convention Center )
Louis Hector Jr., Chemical Sciences and Materials Systems, General Motors R&D, Warren, MI

Multiscale modeling techniques are currently being used to predict material properties that rely upon information that spans atomic to engineering length scales. Often absent in existing models is physics-based materials science that does not rely on data fitting. In this presentation, we will describe a quantitative, parameter-free theory of solute strengthening of metal alloys, with application to both aluminum and magnesium. An expression for the alloy yield strength as a function of temperature and strain rate is informed with solute-dislocation energetics computed with first principles density functional theory (DFT) and a lattice Green’s function method. For Al alloys, strengthening due to Mg, Cr, Cu, and Si solutes is quantified. For Mg, focus will be on strengthening of basal flow stress in Mg-Al alloys. Key differences in strengthening due to the size of the equilibrium dislocation core structures will be emphasized. The model is readily extended to other solute chemistries and dislocation types and provides a basis for exploring the chemistry of deformation.

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