Study on Secondary Recrystallization of Cold-rolled Aluminium Single Crystal (2nd Report)

Abstract

The author has already reported that a coarsening phenomenon was observed, when 75% rolled Al single crystals were heated up to 550°. So, in this 2nd report the author investigated the region of orientation and cold reduction in which the coarsening phenomenon was observed and then measured the change of physical properties due to the coarsening phenomenon. The investigation was carried out with Al single crystal of 99.994% purity, and the following results were obtained: (1) By increasing the cold reduction, the region of orientation where the coarsening phenomenon is observed, spreads toward (100) direction from (111) and (111)-(110) directions in a unit stereographic triangle, and becomes the greatest at 75∼80% reduction. In this region the (111) specimen has the most violent tendency of coarsening. But the coarsening phenomenon was not observed following a cold reduction under 50% or above 95%. (2) By measuring the electric resistance, the specific heat, the hardness and by X-ray, analysis there were recognized differences between (111) and (100) or (110) specimens, that is, (111) specimen sustains severer lattice distotrion rather than specimens oriented otherwise in rolling, and its hardness is the highest. In consequence, when annealed, the (111) specimen recrystalizes earlier than the others, and after recrystallization it maintains the strong preferred orientation.