温間圧延による5083系アルミニウム合金板材の結晶粒微細化

抄録

An attempt was made to refine the grain structure of the 5083 based aluminum alloy containing Zn, Cu and Zr, by employing a new warm rolling method under the control of both roll temperature and material temperature. Samples were rolled at temperature ranging from 200°C to 400°C with re-heating after each rolling pass in order to keep sample temperature. As rolling temperature gets higher, the subgrain structure becomes more stable. In the case of rolling at 400°C, fine grains with diameter less than 3 μm are observed after final annealing. It is also found that the sheet rolled at 400°C has a high ratio of low angle boundaries, less than 15°, after final annealing. On the other hand, the sheets rolled at below 250°C show a fully recrystallized structure. The warm-rolled sheets have strong β-fiber orientations. There is no apparent change caused by the subsequent annealing in the orientation density of the β-fiber in the sheet rolled at 400°C. The yield strength of a sheet in O-temper rolled at 400°C is 40% higher than that of a cold rolled sheet.