CAREER: Fundamental investigation of twin boundary engineering through cyclic cross-phase-boundary thermomechanical processing

非技术性总结该学院早期职业发展(Career)奖支持研究和教育活动，以开发材料加工策略，以制造更坚固和/或更具延展性的钛(钛)合金。钛合金的力学性能受材料中存在的缺陷和其他精细结构的影响很大，这些缺陷和组织的预测或设计是具有挑战性的。在这个项目中，首席研究员和她的团队将开发不同长度尺度的模型，以计算预测钛合金在热和机械载荷下精细结构的演变。这项研究将为合理地生产钛合金的精细组织，从而获得所需的机械性能提供策略，这将有利于航空航天、汽车和其他对钛合金有越来越大需求的行业。该项目将把研究和教育活动紧密结合在一起，包括科学展览、课程开发、研究指导、在线教育和研究工具共享，以“强韧金属合金”为总主题，培养不同层次的K-12、本科生和研究生水平的学生，以培养一支综合材料和力学知识的科学队伍。该项目将使在线和面对面的参与者都可以访问开发的教育模块和研究工具。技术总结该职业奖支持旨在建立基于物理的热机械加工路径的研究和教育活动，以合理地在钛合金中创建所需的微观结构。钛合金的力学性能直接取决于其微观组织，包括孪晶界、位错、相界和晶界。因此，开发有效的形变加工策略来控制钛合金的组织是势在必行的。为了实现这一目标，PI和她的团队将进行三项研究，重点是：(I)使用原子模拟和第一性原理计算来阐明钛合金的微观组织形成机制；(Ii)通过相场有限元模拟将微观组织演变的原子机制提升到宏观力学；以及(Iii)开发跨相界热机械路径来控制钛合金的微观组织的形成。该项目将促进对钛合金组织演变的基本认识和建模，促进钛合金热机械加工方法和合金成分的发展。该项目将把研究和教育活动紧密结合在一起，包括科学展览、课程开发、研究指导、在线教育和研究工具共享，以“强韧金属合金”为总主题，培养不同层次的K-12、本科生和研究生水平的学生，以培养一支综合材料和力学知识的科学队伍。该项目将使在线和面对面的参与者都可以访问开发的教育模块和研究工具。该项目由材料研究部门(通过凝聚态物质和材料理论以及金属和金属纳米结构计划)和土木、机械和制造创新部门(通过材料和结构力学计划)联合资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL SUMMARYThis Faculty Early Career Development (CAREER) award supports research and education activities to develop material processing strategies to manufacture stronger and/or more ductile titanium (Ti) alloys. The mechanical properties of Ti alloys are significantly affected by the defects and other fine structures present in the material, which are challenging to predict or design. In this project, the principal investigator and her team will develop models at different length scales to computationally predict the evolution of fine structures in Ti alloys under thermal and mechanical loadings. The research will lead to strategies to rationally produce fine structures in Ti alloys, thus obtaining desired mechanical properties, which will benefit aerospace, automotive, and other industries that have an increasing demand of Ti alloys. This project will tightly integrate research and educational activities, including science exhibits, curriculum development, research mentoring, online education, and research tool sharing, with an overarching theme of “strong and ductile metal alloys” to train a diverse body of students at the K-12, undergraduate, and graduate levels toward fostering a scientific workforce with integrated knowledge of materials and mechanics. The project will make the developed education modules and research tools accessible to both online and in-person participants.TECHNICAL SUMMARYThis CAREER award supports research and education activities aimed at establishing physics-based thermomechanical processing pathways to rationally create desired microstructures in Ti alloys. Mechanical properties of Ti alloys are directly determined by their microstructures, including twin boundaries, dislocations, phase boundaries, and grain boundaries. It is, therefore, imperative to develop effective thermomechanical processing strategies to control microstructures in Ti alloys. To achieve this goal, the PI and her team will pursue three research thrusts that focus on (i) elucidating microstructure formation mechanisms in Ti alloys using atomistic simulations and first-principles calculations; (ii) upscaling the atomistic mechanisms of microstructure evolution to macroscopic mechanics through phase-field finite element modeling; and (iii) developing cross-phase-boundary thermomechanical pathways to control the formation of microstructures in Ti alloys. The project will advance the fundamental understanding and modeling of microstructure evolution in Ti alloys, accelerating the development of thermomechanical processing approaches and alloy compositions of Ti alloys. This project will tightly integrate research and educational activities, including science exhibits, curriculum development, research mentoring, online education, and research tool sharing, with an overarching theme of “strong and ductile metal alloys” to train a diverse body of students at the K-12, undergraduate, and graduate levels toward fostering a scientific workforce with integrated knowledge of materials and mechanics. The project will make the developed education modules and research tools accessible to both online and in-person participants.This project is jointly funded by the Division of Materials Research (through the Condensed Matter and Materials Theory and Metals and Metallic Nanostructures programs) and the Division of Civil, Mechanical, and Manufacturing Innovation (through the Mechanics of Materials and Structures program).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.