THE EFFECT OF DILUTE COPPER AND GERMANIUM ATOMS FOR STAGE IIA RECOVERY IN COLD-WORKED ALUMINUM

Wires of pure aluminum and Al-Ge, Al-Cu dilute alloys are deformed abo ut 10% in length at 4.2 K. The electrical resistivity after isochronal annealing in the temperature range from 20 to 160 K is measured at 4. 2 K. A recovery consisting of two sub-peaks at around 75 and 90 K is o bserved in stage IIa (60 to 100 K). The 90 K recovery peak is suppress ed effectively by Ge atoms, while Cu atoms suppress both 75 and 90 K p eaks uniformly. The suppression effects increase with increasing impur ity concentration in the alloys and are discussed from the point of vi ew of the solubility of Ge and Cu atoms.