The Relationship Between Grain Structure and Deformation Behavior to the Fracture Mechanism in High Strength-High Ductility Combination Nanostructured Materials

非技术摘要所提出的关于下一代高强度材料的研究被设想为扩展具有上级可成形性的高强度-高延展性合金的加工的最新技术水平。揭示高强度高塑性复合材料的断裂机制将是指导强韧金属材料发展的重大突破。最终的目标是确定指导方针，开拓一个新的前沿的高强度，高韧性材料的重量轻，效率高的解决方案，涉及能量吸收和成形性。 此外，还将开发新技术来了解适用于其他金属系统的材料行为。纳米晶粒材料的高强度-高延展性组合将允许更薄的截面或部件，这将导致运输部门的燃油经济性。技术摘要该奖项的研究目标是确定在获得高强度-高延展性组合的金属晶粒尺寸在纳米范围内的基本标准。该标准将通过进行受控的机械变形实验结合变形区域的研究，通过显微镜工具来阐明。实验将涉及随着晶粒尺寸的减小而增加主要成分的稳定性。该标准将定义金属材料的主要成分的稳定性是否负责控制高强度金属材料的延展性和延迟断裂。变形行为的变化将作为从纳米晶粒制度到传统的微米制度的晶粒尺寸的函数进行研究。将根据晶粒尺寸、变形过程和断裂机制之间的相互关系，开发具有预测能力的各种材料系统的物理模型。

Non-technical Abstract The proposed research concerning the next generation of high strength materials is envisaged to extend the state-of-art of processing of high strength-high ductility alloys with superior formability. The unlocking of fracture mechanisms underlying high strength-high ductility combination will be a major breakthrough in guiding the development of strong and ductile metallic materials. The ultimate objective is to determine guidelines to pioneer a new frontier of high strength-high ductility materials for light and efficient solutions involving energy absorption and formability. Furthermore, new techniques will be developed to understand material behavior that will be applicable to other metallic systems. The high strength-high ductility combination of nanograined materials will allow for thinner sections or components, which will lead to fuel economy in the transportation sector.Technical AbstractThe research objective of the award is to determine the fundamental criteria in obtaining high strength - high ductility combination in metals with grain size in the nanometer range. The criteria will be elucidated by conducting controlled mechanical deformation experiments in conjunction with the study of deformed region via microscopy tools. Experiments will involve increasing the stability of the principal constituent with decrease in grain size. The criteria will define if the stability of the principal constituent of the metallic material is responsible in governing the ductility and delayed fracture of high strength metallic materials. The changes in deformation behavior will be studied as a function of grain size from nanograin regime to conventional micrometer regime. Physical models with predictive capabilities for a wide range of material systems based on the inter-relationship between grain size, deformation process and fracture mechanisms will be developed.