Plastic deformation and forming behavior of high strength aluminum alloys for automotive applications

低强度汽车铝合金的成形对于汽车车身板件来说是相对常见的。然而，在成形应用中使用高强度铝合金来制造汽车结构在过去一直是一个具有挑战性的问题，因为它们的可成形性较低。由于需要进一步减轻汽车重量以解决汽车排放相关的环境问题，因此对这些合金重新产生了兴趣。微观结构和可成形性之间的关系的基本理解，这些合金的开发和使用的关键，是必要的。这项研究计划旨在填补这一空白。 拟议的研究计划涉及两个高强度铝（HSA）板合金，X615和AA7075的材料微观结构的尺度上的实验和计算建模研究。拟议的研究将在晶粒和颗粒结构方面表征这些合金的3D微观结构，在微观结构的尺度上进行力学测试，并开发微观结构与这些材料的塑性流动，成形性和断裂之间的关系。这项研究将利用实验技术，能够量化三维微观结构和空间应变分布附近的微观结构的异质性。微观结构将由具有统计学意义的参数表示，并通过现代统计分析工具进行分析。此外，三维空间性质和微观结构成分的本构特性将被纳入先进的计算模型，系统地探索微观结构成分的作用，对塑性流动，可成形性，损伤和断裂行为的试样和组件从HSA板材。基于有限元方法的计算模型将用于指导材料开发和预测HSA板材的成形性能。此外，计算模型将能够系统地评估在参数研究中单个微观结构参数对材料变形和损伤行为的作用。由于对微观结构的精确控制，这样的研究是昂贵的并且难以在实验上进行。 模拟研究将导致更好地理解应变调节和局部化，损伤和高强度铝合金的失效过程的微观力学。建模研究的结果将加速现有HSA和其他板材的进一步开发，以提供更好的成形性和轻量化汽车铝部件的使用寿命，并为汽车零件成形的材料选择提供明确的指导方针。

The forming of low strength automotive aluminum alloys is relatively common for automotive body panels. The use of high strength aluminum alloys in forming applications to create automotive structures, however, has been a challenging problem in the past due to their lower formability. There has been renewed interest in these alloys due to the need for further weight reduction of automobiles to address automotive emission related environmental concerns. A fundamental understanding of the relationship between microstructure and formability, critical to the development and use of these alloys, is needed. This proposed research program is intended to fill this gap. The proposed research program deals with experimental and computational modeling studies at the scale of material microstructure on two high strength aluminum (HSA) sheet alloys, X615 and AA7075. The proposed study will characterize the 3D microstructures of these alloys in terms of grain and particle structure, perform mechanical tests at the scale of the microstructure, and develop relationship between microstructure and plastic flow, formability, and fracture of these materials. This study will make use of experimental techniques that are capable of quantifying 3D microstructures and spatial strain distributions in the vicinity of microstructural heterogeneities. The microstructure will be represented by statistically significant parameters and analyzed by modern statistical analysis tools. In addition, 3D spatial nature and constitutive properties of microstructural constituents will be incorporated into advanced computational models to systematically explore the role of microstructure constituents on plastic flow, formability, damage, and fracture behavior of test specimens and components made from HSA sheet materials. The computational model based on the FE method will be used to guide material development and prediction of forming performance of HSA sheet materials. Additionally, the computational models will be able to systematically evaluate the role of individual microstructural parameters on material deformation and damage behaviour in a parametric study. Such studies are costly and difficult to carry out experimentally due to precise control of the microstructure. The modeling study will lead to a better understanding of micro-scale mechanics of strain accommodation and localization, damage, and failure processes in high strength aluminum alloys. The results of the modeling study will accelerate further development of existing HSA and other sheets to provide better formability and service life of lightweight automotive aluminum parts, as well as provide clear guidelines for material selection for automotive part forming.