DISLOCATION SUBSTRUCTURES FORMED DURING THE FLOW-STRESS RECOVERY OF HIGH-PURITY ALUMINUM

Flow stress recovery experiments were performed on polycrystalline high purity aluminum following room temperature tensile prestrains of 5%, 15%, 20% and 25%. Isothermal recovery temperatures of 120, 160 and 200 degree C were used for recovery times up to 300 h. It was found that work hardening at room temperature is accompanied by the development of dislocation tangles that form the boundaries of a dislocation cell structure. The cell structure converts to a sharply defined subgrain structure during recovery as the tangles are rearranged into networks. The network planes are the same as those on which the original tangles were formed.