KSEF R&D Excellence: Processing of Ultra-Fine Grain CC AA 3003 Aluminum Alloy and its Formability Improvement

Twin-belt continuous cast processing of aluminum sheets has recently gained extensive attention because of its high productivity and low conversion cost. Aluminum sheet produced by continuous casting (CC) provides an energy savings of at least 25% and an economic savings of more than 14% over sheet made from conventional direct chill (DC) cast ingots. Due to different processing routes, there are distinct differences in microstructure and texture between CC and DC hot bands, which affect the evolution of microstructure and texture during subsequent processing and the formability of aluminum sheets. Therefore, strict control of microstructure and texture is necessary to improve the formability of CC aluminum sheets. The goal of the proposed research is to improve the formability of CC AA 3003 aluminum alloy sheets through the quantitative analysis of the evolution of microstructure and texture during thermomechanical processing and their effects on the formability. The plan of the proposed work is outlined below: . Mechanical processing of ultra-jine grain aluminum alloys. The presently produced CC AA 3xxx series aluminum alloys exhibit large elongated grains (> 100 ~m), which decrease significantly the formability of aluminum sheets. In this project, the recrystallization kinetics and recrystallized grain size of CC and DC AA 3003 aluminum alloys will be investigated in detail. The parameters of the CC processing will be proposed for in-line annealing of this alloy. Through the optimization of the processing parameters, aluminum sheets with fine equiaxed grains (~ 10 ~m) will be produced. . Formation of recrystallization texture {113} and its effect on formability. We have recently found a new recrystallization texture {113} in CC AA 3003 aluminum alloy in addition to the P texture {11O}. Studies of this new texture and its effect on formability are not only of intense academic interest, but also of critical importance for technological applications. . Prediction and control of crystallographic texture. As described in detail later, the approach for the prediction and control of crystallographic texture, which was recently advocated by Liu and Morris, will be applied to CC AA 3003 aluminum alloy. This work will mainly focus on the effects of grain shape, grain size, and particles on the texture evolution and seek a quantitative treatment that incorporates all mathematical formulae to predict and control the crystallographic texture during thermomechanical processing. . A texture optimization study for minimum earing: A quantitative analysis relation of the earing profile or earing value and texture volume fractions will be established by using the theory of crystal plasticity for the prediction of the earing value. The constants in the quantitative relation will be obtained from experimental data. The aluminum industry in the state of Kentucky is the third largest contributor to the state's economy. Energy and cost savings are of utmost important to this industry. Full scale implementation of this proposed research effort by the year 2015 could lead to a yearly energy saving of 23 trillion Btu's and related energy cost savings of $96 million per year for the aluminum rolled product industry. The University of Kentucky has been working with Commonwealth Aluminum Corporation (a Kentucky corporation and the leading manufacturer of Hazelett cast (continuous cast) aluminum sheets in North America) for 17 years on several R&D programs. The indicated research team is uniquely qualified to work on the proposed research. Keywords: Aluminum; Texture; Recrystallization; Formability; Thermomechanical processing 5 Rand D Excellence KSEF-04-RDE-007