Single-crystal <111> and <001> Al specimens of 4N-purity material were deformed in tension to strains of about 20%. In all specimens, multiple slip structures without deformation bands were observed. In <111> specimens deformed at 293K, fine wavy slip traces were recognized because of the difficulty of cross slips. The difficulty was due to the tensile-orientation dependence of cross slips. The dislocation structure exhibited layered cell structures composed of cell walls with a high dislocation density. In <001> specimens deformed at liquid-N temperatures, complex fine slip traces similar to those in the case of <111> room-temperature specimens were also observed because of the difficulty of cross slips. This difficulty was due to the temperature dependence of cross slips. The dislocation structure comprised small isotropic cells with a high dislocation density around their cell walls. In the above 2 kinds of deformed Al single crystals, the formation of recrystallized grains was very easy. On the other hand, in <001> specimens deformed at room temperature, many cross-slips with large steps were seen because all of the 8 primary slip systems had a geometrically appropriate (another primary) cross slip system. The dislocation structure exhibited polygonal cells with a low dislocation density. During annealing, no recrystallized grain was formed in the specimen. The stress values of the stress-strain curves in the <001> (room temperature), <111> (room temperature)

and <001> (liquid-N temperature) specimens were 22MPa at 25% strain, 71MPa at 22% and 106MPa at 20%, respectively.

Effect of Cross-Slips on Deformation Microstructure and Recrystallization in <111> and <001> Al Single Crystals. M.Tagami, K.Kashihara, T.Okada, F.Inoko: Materials Transactions, 2001, 42[9], 2013-20