Deformation Behavior of High Purity Aluminum Single Crystals under Repeated Biaxial Compressions

The texture and hardness of high purity aluminum single crystals that have been deformed by recurrent biaxial compression were investigated. Three types of specimens, WW, BW, and RR, were prepared using a modified Bridgeman method. The two compression axes were [100] and [0-10] in WW, [101] and [0-10] in BW, and [596] and [15 -11 4] in RR. The specimens were deformed along one compression axis under plane strain conditions at a strain of 0.25, and then they were deformed along the other axis at the same strain conditions. Biaxial compressions up to eight times were repeatedly performed, for which the cumulative strain was 2. The textures of all the specimens after eight biaxial compressions showed that the average crystal orientations were within approximately 15° relative to the initial orientations. Textures were formed because of the forward/inverse slips of identical active slip systems during biaxial compression. The hardness tests of the three specimens indicated an obvious dependency on initial orientation. The WW specimen exhibited the lowest hardness value, which was ascribed to the occurrence of cross slips that continued for the eight biaxial compressions.