GOALI: Plastic Anisotropy and Bauschinger Effect: Fundamental Role of Second-Phase Particles

该项目解决了与沉淀硬化铝合金形成行为有关的材料和力学问题，这些铝合金表现出优选的取向（纹理）和方向相关的特性（各向异性）。这项研究的目的是了解铝合金在成形过程中的回弹，这已经限制了它们在许多金属成形应用中的使用。对这些行为的基本理解将导致与这类重要结构材料形成相关的成本降低。该项目是一个高度利用的合作研究项目，旨在澄清和扩展金属本构方程的微观结构基础，以包括第二相颗粒对各向异性硬化的影响。该项目的目标包括由工业合作伙伴（美国铝业技术中心或ATC）加工Al-Ge-Si模型合金，热处理以产生不同的显微组织，并在析出物尺寸，取向，形貌，晶粒尺寸等方面对第二相显微组织进行全面表征。该研究将建立析出相组织与各向异性硬化之间的基本联系。合金的表征使用了先进的技术，如定向成像显微镜（OIM）和透射电镜，以及广泛的力学测试和力学建模，从而得到输入有限元程序的本构形式。该项目利用了俄亥俄州立大学（OSU）和ATC的专业知识和实验设施。这项工作的教育影响在于研究生通过暑期实习与行业同行的密切接触以及ATC合作研究者的研究方向。该项目是俄勒冈州立大学和ATC之间的密切合作，对金属，机械和制造业的研究领域具有横切意义。该研究扩展了对第二相组织在产生各向异性硬化行为中的作用的基本认识。这些知识对于许多研究发展和商业应用都是重要的，对于包括航空航天和汽车在内的许多技术来说，铝合金成形操作的成本降低是合理的。大学人员与工业界同行的密切合作为学生提供了重要的机会

This project addresses the materials and mechanics issues involved in the forming behavior of precipitation hardened aluminum alloys that exhibit preferred orientations (textures) and directionally dependent properties (anisotropy). The study is aimed at understanding the springback of aluminum alloys during their forming operations that has hither to limited their use in many metal forming applications. The fundamental understanding of these behaviors will lead to the reduction in cost associated in forming of this important class of structural materials. The project is a highly leveraged cooperative program of research directed to clarify and extend the microstructural basis of metallic constitutive equations to include the effects of second-phase particles on anisotropic hardening. The objectives of the project include processing of model alloys of Al-Ge-Si by the industrial partner (Alcoa Technical Center or ATC), heat-treatments to produce different microstructures and a thorough characterization of second-phase microstructures in terms of precipitate size, orientation, morphology, grain size, etc. The study will establish fundamental linkages between the precipitate structure and anisotropic hardening. The alloy characterization is performed using advanced techniques such as orientation image microscopy (OIM) and TEM along with extensive mechanical testing as well as mechanics modeling leading to constitutive forms for inputting into finite element programs. The project takes advantage of the expertise and experimental facilities available at both the Ohio State University (OSU) and ATC. The educational impact of this work lies in close contact of the graduate students with the industrial counterpart through summer internships as well as the research direction by the co-investigator from ATC.%%%The project is a close collaboration between OSU and ATC with crosscutting implications to research areas in metals, mechanics and manufacturing. The study extends the fundamental understanding of the role of second- phase structures in producing anisotropic hardening behavior. Such knowledge is important for many research developments as well as commercial applications, with plausible cost reduction in the forming operations of aluminum alloys that are important for many technologies including aerospace and automotive. The close collaboration of the university personnel with the industrial counterparts provides significant opportunities for students.***