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

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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.***