It is known that at room temperature the tensile stress-strain curve of an aluminum single crystal having <100> tensile orientation becomes flat after about two percent elongation (this flat region of the stress-strain curve is named Stage IV). In the previous paper, the propagation of clustered slip accompanied by prominent cross slip was observed in the Stage IV region of curve.
In the present study, the <100> oriented aluminum single crystals were tested in tension at various temperatures so as to clarify the influence of temperature on the deformation mechanisms in Stage IV.
At 203K, a few clustered slip lines accompanied by prominent cross slip occurred, but they did not propagate in the entire region of the specimen, and the stress-strain curve became flat only from about ten percent elongation. In the crystal stretched at 77K, the cluster did not propagate at all from the both ends of the specimen, and so the stress-strain curve did not become flat.
On the other hand, the wavy coarse slip was observed and the stress-strain curve became flat from about 0.5 percent elongation at 473K. It was suggested that these wavy slip lines were produced by frequent repetition of cross slip on two {111} planes and also possibly on {110} plane having the same slip direction.
It was confirmed that the occurrence of Stage IV is caused by the propagation of the clustered slip accompanied by prominent cross slip and is much influenced by the temperature of deformation due to the easiness of cross slip.
