Reduction of Annealing Times for Energy Conservation in Aluminum

Abstract

and the Pennsylvania Technology Investment Authority (PTIA) to make processing of aluminum less costly and more energy efficient. Researchers in the Department of Materials Science and Engineering have investigated how annealing processes in the early stages of aluminum processing affect the structure and properties of the material. Annealing at high temperatures consumes significant amounts of time and energy. By making detailed measurements of the crystallography and morphology of internal structural changes they have generated new information that will provide a scientific basis for shortening processing times and consuming less energy during annealing. Background:The status of the Domestic Technology for the thermomechanical processing of aluminum alloy intended for sheet and plate product is as follows. Hot rolling processes are aimed at breaking down as-cast structures in Direct-Chill (DC) ingots. Critical to the success of this stage of the processing is the refinement of the as-cast microstructure in terms of both grain morphology and the crystallographic orientations present; we will refer to the latter as texture. 2 particularly important to the application of such materials as 5xxx for can closures and 3xxx for beverage can stock. In particular, it is standard practice to anneal partially broken-down slabs for long times in order to ensure that recrystallization is completed before continuing the hot rolling process. Simple models exist that describe the rate at which the recrystallization process takes place but no information is available on the texture development. This proposal project will remedy that lack by measuring texture-dependent recrystallization rates (kinetics). Status:The project is complete. Three different commercial purity aluminum alloys (AA1050, AA5005 and AA3003) were studied. The main applications of these (non-heat treatable) alloys are beverage cans, automotive products etc. Recrystallization and texture evolution are two very important transformations in the thermo-mechanical processing of these alloys. These transformations are of critical importance for aluminum industry as they are directly related to energy consumption and properties of the finished products. The main aim of this project is to further increase our current understanding of recrystallization and texture evolution using advanced analytical tools like Electron Backscatter Diffraction (EBSD). The project was divided into two main parts -experimental data collection and extraction of critical parameters from experimental data forming one part and simulation of recrystallization from the experimental data and comparison of experimental results with simulation being the other part. The experimental data collection and analysis involved annealing of asreceived samples and scanning them in an EBSD system. The main approach followed in the experimental analysis was that of identification of the most important parameters required for quantification of recrystallization and texture evolution. This analysis required de...