Structural studies of binary and ternary Al alloys

目前的建议将允许系统的研究工作的发展，其重点是工业重要性的铝合金的结构-性能关系。研究对象为纯Al、Al-1at%Mg、Al-3at%Mg、Al-1at%Mg-1at%Si和Al-0.2at%Cr等二元和三元模型体系。 建议的程序假设全面研究的机械和电气性能和各种微观结构的特点，在4.2K和300 K之间的温度范围内的塑性流动过程中开发。该项目将允许阐明合金元素如Mg，Si和Cr以及其他微观结构元素（包括位错和点缺陷）对铝合金成形性的贡献。实验将在这些材料的充分表征的多晶体上进行。将采用申请人实验室中可用的独特变形设施以及SEM-OIM技术、TEM技术（如弱束TEM和HREM）和电阻率测量来研究导致高应变区域中断裂的过程。该研究还将解决有关的问题，在materal中积累的缺陷的性质，这些缺陷存储在晶格中的最大密度，和内在的不稳定性的变形结构在断裂的开始。这些问题对于理解合金成分、变形亚结构与冷加工铝合金塑性极限之间的关系具有基础性意义。这些知识可用于开发新合金，这些合金将表现出更好的功能特性组合，以用于汽车应用。实验将与理论上的努力，在这些材料的变形行为模型的基础上可用的方法。对合金行为的详细了解将提高加工操作的可靠性，从而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.