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

铝、镁和钛的轻质结构合金在分立产品部门的应用中具有重要的技术价值，包括汽车、航空航天、能源系统和生物医学应用。在制造过程中，通常使用挤压、轧制、板材加工和成形方法等变形工艺来成形这些金属系统的部件。由这些工艺产生的零件的表面质量属性，如缺陷、光洁度和强度，在很大程度上由表面金属流动的性质决定。这种表面流动在控制成形界面处的摩擦和磨损方面也起着主要作用。由于这些原因，迫切需要研究变形加工中流动的基本性质，以便通过适当地控制流动来提高成分和产品质量。该奖项将通过支持在关键工业部门推进最先进的制造工艺技术的研究来满足这一需求。与这项研究相辅相成的是一个教育项目，让本科生研究人员参与创建一个行业流动的视频库，并适度关注在研究生学习中培养创业精神。这项研究将研究一种具有三个协调推进的模型工艺系统--一个硬模具(楔子)滑动到一个工件上。首先，变形科学计划将利用现场观测技术对工件表面和接触处的流动进行高分辨率分析。表面的流动现象(如层流、弯曲、不稳定)、应变场和应变率场将作为可控工艺参数的函数进行分析。将探索流动类型、摩擦和缺陷形成之间的相互作用。其次，将从显微组织、缺陷结构、机械性能和表面形貌等方面检查工件的表面质量。表面质量属性将与流场相关联。第三，表面流动将使用包含材料非均质性和颗粒水平结构的连续介质方法来模拟。通过整合分析结果，将创建一张工艺图，根据关键材料和工艺参数划分流程和缺陷。这项研究将专门针对铝、镁和钛的模型低密度结构合金进行，选择这些合金是因为它们的实验适宜性以及与离散产品部门的重量减轻直接相关。这些技术和发现将影响材料加工、摩擦学、可塑性和地球物理折叠现象等多个领域。

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.