Direct In Situ Analysis of Surface Flow Fields in Deformation Processing of Lightweight Structural Metals

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Light-weight structural alloys of aluminum, magnesium and titanium are of technological interest for use in applications in the discrete products sector, encompassing automotive, aerospace, energy systems and biomedical applications. Deformation processes such as extrusion, rolling, sheet-metal working, and forming methods are typically used to shape components from these metallic systems during manufacturing. The surface quality attributes of components, such as defects, finish and strength, created by the processes is to a large extent determined by the nature of metal flow at the surface. This surface flow also plays a major role in controlling friction and wear at the forming interfaces. For these reasons, there is a critical need for studying the fundamental nature of the flow in deformation processing so that component and product quality can be enhanced by suitable control of the flow. This award will address this need by supporting research to advancing the state-of-the-art of manufacturing process technologies in key industrial sectors. Complementing the research is an education program involving undergraduate researchers in creating a video gallery of flows for industry, and a modest focus on fostering entrepreneurship in graduate study. The research will study a model process system - a hard die (wedge) sliding against a workpiece - with three coordinated thrusts. Firstly, a deformation science initiative will utilize in situ observational techniques for high-resolution analysis of flow at workpiece surfaces and contacts. Flow phenomena (e.g., laminar, sinuous, instabilities), strain and strain rate fields, at the surfaces will be analyzed as a function of controllable process parameters. The interplay between flow type, friction, and defect formation will be explored. Secondly, workpiece surface quality will be examined in terms of microstructure, defect structures, mechanical properties, and topography. The surface quality attributes will be correlated with the flow fields. Thirdly, surface flow will be modeled using continuum approaches that incorporate material heterogeneity and grain level structure. By integrating the analyses results, a processing map, that demarcates flows and defects in terms of key material and process parameters, will be created. The study will be conducted specifically on model low-density structural alloys of aluminum, magnesium and titanium, selected for their experimental suitability and direct relevance to weight reduction in the discrete products sector. The techniques and findings will impact areas as diverse as materials processing, tribology, plasticity, and geophysical folding phenomena.