BRIGE: Anisotropic Deformation and Damage Mechanisms in Al-Mg Bi-modal Grain Size Alloy

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The research objective of this BRIGE award is to investigate physical mechanisms of inelastic deformation and damage in Al-Mg bi-modal grain size alloys. Effect of different parameters such as strain rate, microstructure, temperature, and anisotropy on physical mechanisms of damage will be investigated through experiment. In order to explore the deformation mechanisms of larger grains and nano-crystalline matrix separately and to be able to evaluate the contribution of these two, specimens without large grains and with different volume ratios of large grains are tested. Due to anisotropic nature of these materials, the tests will be conducted in different orientations to compare the deformation rates and mechanisms as well as strength. Microstructural analysis will be conducted before and after test using SEM and TEM to explore deformation mechanisms and microstructural evolution. Micro-structural based constitutive models will be developed for this material to model inelastic deformation. If successful, the results of this research will provide fundamental science and technology on polycrystalline plasticity and damage mechanisms as well as constitutive equations for Al-Mg bi-modal grain size alloys. These constitutive equations will take the microstructural effect into account and will be capable of determining the deformation rates in different orientations. In addition, the results from these studies will provide the necessary framework, experimental techniques, and knowledge to allow investigations of cyclic fatigue and damage in micro structurally non-uniform anisotropic material. This knowledge will assist the community in designing more reliable, cost effective and intelligent structures. Broader societal impact of this project is enhanced by outreaching women and minorities and underrepresented groups, attracting k-12 students to higher education in the area of science and technology and enriching graduate and undergraduate curriculum through systematic channels.