Insights into deformation mechanisms from atomistic simulations: The case of oxygen in titanium
Mark Asta, University of California, Berkeley, Berkeley, USA
The past decade has witnessed a rapid increase in the use of first-principles calculations and classical atomistic simulations to guide the discovery and design of materials for applications across a broad range of technologies. For structural materials, this type of modeling can be used to provide unique insights into the atomic mechanisms underlying mechanical deformation behavior, which can guide alloy design. In this talk I will illustrate insights gained from atomic-scale modeling in this context, focusing on recent investigations of the dramatic effect of solutes on the deformation behavior of hcp-structured titanium solid solutions. The talk will focus specifically on the origin of experimentally observed changes in deformation microstructures associated with solute content for both Ti-Al and Ti-O alloys. For both systems, experiments observe transitions to planar slip that are associated with increasing solute content. First-principles and atomistic modeling suggest that this behavior stems from two different origins in these two systems, associated with short-range-order softening in the case of substitutional Ti-Al, and a novel slip-induced restructuring in interstitial Ti-O systems. The relevance of these insights to alloy design will be discussed.
Session W2: Wednesday, 27 June 2018