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

该 BRIGE 奖项的研究目标是研究 Al-Mg 双峰晶粒合金中非弹性变形和损伤的物理机制。通过实验研究应变率、微观结构、温度和各向异性等不同参数对损伤物理机制的影响。为了分别探讨大晶粒和纳米晶基体的变形机制，并能够评估两者的贡献，对不含大晶粒和不同体积比例的大晶粒的样品进行了测试。由于这些材料的各向异性性质，测试将在不同的方向进行，以比较变形率、机制以及强度。将使用 SEM 和 TEM 进行测试前后的微观结构分析，以探索变形机制和微观结构演变。将为这种材料开发基于微观结构的本构模型，以模拟非弹性变形。如果成功，这项研究的结果将为多晶塑性和损伤机制以及铝镁双峰晶粒合金的本构方程提供基础科学和技术。这些本构方程将考虑微观结构效应，并且能够确定不同方向的变形率。此外，这些研究的结果将提供必要的框架、实验技术和知识，以便研究微观结构非均匀各向异性材料的循环疲劳和损伤。这些知识将帮助社区设计更可靠、更具成本效益和智能的结构。该项目更广泛的社会影响通过扩大女性、少数族裔和代表性不足群体的影响力、吸引k-12学生接受科技领域的高等教育以及通过系统化渠道丰富研究生和本科生课程而得以增强。

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.