Structural studies of binary and ternary Al alloys

目前的提案将允许开展系统的研究工作，重点是具有工业意义的铝合金的结构-性能关系。研究将在模型二元和三元系统上进行，包括纯Al、Al-1at%Mg、Al-3at%mg、Al-1at%mg-1at%Si和Al-0.2at%Cr。该计划假定对4.2K至300K温度范围内塑性流动过程中形成的各种微观结构特征和机械和电学性能进行全面研究。该项目将有助于阐明镁、硅和铬等合金元素以及包括位错和点缺陷在内的其他微结构元素对铝合金成形性的贡献。实验将在这些材料的表征良好的多晶体上进行。申请人的实验室将使用独特的变形设备，以及扫描电子显微镜和扫描电子显微镜技术、弱束电子显微镜和高分辨电子显微镜等电子显微镜技术，以及电阻率测量来研究在高应变区导致断裂的过程。这项研究还将解决与母体中累积的缺陷的性质、这些缺陷存储在晶格中的最大密度以及变形结构在断裂开始时的内在不稳定性有关的问题。这些问题对于理解冷加工铝合金成分、变形亚结构与塑性极限之间的关系具有重要意义。这些知识可以用于新合金的开发，这种合金将在汽车应用中表现出更好的功能特性组合。这些实验将与基于现有方法对这些材料中的变形行为进行建模的理论工作联系起来。对合金行为的详细了解将提高加工操作的可靠性，因此将提高该行业的生产率。

The present proposal would allow development of systematic research efforts, which focus on the structure-property relationship in Al alloys of industrial importance. The studies will be carried out on model binary and ternary systems, which will include pure Al, Al-1at%Mg, Al-3at%Mg, Al-1at%Mg-1at%Si and Al-0.2at%Cr.  The proposed program assumes comprehensive studies of mechanical and electrical properties and of various microstructural features developed during plastic flow over the range of temperatures between 4.2K and 300K. The project will allow elucidating the contribution of alloying elements such as Mg, Si and Cr and other microstructural elements including dislocations and point defects on the formability of Aluminium alloys. The experiments will be conducted on well-characterized polycrystals of these materials. Unique deformation facilities available in applicants' laboratory, together with SEM-OIM techniques, TEM techniques such as weak-beam TEM and HREM, and electrical resistivity measurements will be employed to study processes, which lead to fracture in the region of high strains. The study will also address the questions pertaining to the nature of defects acumulated in the matrial, the maximum density of these defects stored in the lattice, and the intrinsic instability of deformation structures at the onset of fracture. These questions are of basic significance for the understanding of the relationship between alloy composition deformation substructure and the limits of plasticity in the cold worked Al-alloys. This knowledge can be used for the development of new alloys, which will exhibit better combination of functional properties to be utilized in automotive applications. The experiments will be linked with theoretical efforts to model deformation behaviour in these materials based on available approaches. The detailed knowledge of alloy behaviour will improve the reliability in processing operations and therefore will increase productivity in this industry sector.