1. Forced chemical mixing during severe plastic deformation Robert Averback, University of Illinois at Urbana-Champaign, DMR 1005813 Understanding materials processes occurring far from equilibrium is critical to developing new high- strength materials with enhanced properties. Here we explore using high pressure torsion experiments how an immiscible ternary alloy, Cu 85 Ag 10 Nb 5 responds to severe plastic deformation. The key findings are: Strongly immiscible alloys such as Cu and Nb do not completely mix during severe plastic deformation. Rather they remain two-phase, but with their terminal solubilities highly enhanced. The Ag component is less immiscible in Cu, and it completely dissolves during shearing. Shear mixing is thus guided by chemical interactions. Independent of the initial alloy morphology, the highly immiscible Nb alloy component undergoes a self organization reaction to form precipitates of a fixed size, ≈ 20 nm, remarkably, even at temperatures too low for thermal diffusion. These findings will expedite the development of new processing schemes of advanced nano-composite materials with unique properties. They also provide new insights into such processes as sliding wear, erosion, and fatigue. Size distributions of Nb particles for as-annealed (left) and highly strained (right) samples. The distribution at right does not change with additional straining, indicating patterning. Elemental concentration maps for as-annealed and highly strained samples imaged by Atom Probe Tomography. From left to right are Nb, Cu and Ag concentration maps. For the as-annealed sample, all 3 elements are phase separated. After high strain, Ag and Cu completely mix, but Nb stays phase separated. Concentrations scale with color wavelength: blue = 0; red = 1.

2. Forced chemical mixing during severe plastic deformation Robert Averback, University of Illinois at Urbana-Champaign, DMR 1005813 Undergraduate laboratory on materials processes occurring far from equilibrium: The procedures developed in this research have been transferred to the Senior Metals Laboratory to teach materials processes far from equilibrium.. The Laboratory has three primary goals: Provide a deeper understanding of the concepts of non- traditional processing and the structure-properties relationships of advanced far-from-equilibrium metals. Provide training for using advanced characterization tools. Develop interest and excitement amongst undergraduate students for careers in materials research Below is a picture of the class at Caterpillar, where they presented their failure analysis results on tractor parts supplied by Caterpillar that had failed in service. Senior metals class of 2012 visiting Caterpillar metals laboratory An example of an undergraduates’ work is illustrated above. The SEM image above shows the microstructure of a quenched, near eutectic Al-Cu alloy. The students prepare the alloy by quenching and perform SEM observations. Eutectic alloys are particularly illuminating to students as they illustrate the importance of kinetic pathways. In this case the system undergoes chemical patterning (self-organization), which is a main theme of our NSF research. One of the graduate students supported on this project (M. Wang) supervises this part of the Laboratory. SEM image of quenched Al-Cu near the eutectic composition