J. Phys. Colloques
Volume 48, Numéro C8, Décembre 1987Fifth European Conference on Internal Friction and Ultrasonic Attenuation in Solids
|Page(s)||C8-417 - C8-422|
J. Phys. Colloques 48 (1987) C8-417-C8-422
INTERNAL FRICTION ASSOCIATED WITH THE RE-SOLUTION AND PRECIPITATION OF THE θ - PHASE ALONG THE GRAIN BOUNDARIES AND IN THE MATRIX OF ALUMINIUM-COPPER ALLOYSP. CUI et T.S. KÊ
Institute of Solid State Physics, Academia Sinica, Hefei, China
Low frequency internal friction and elastic modulus measurements were made with aluminium containing 0.015 to 1.2 wt % Cu. (1) When Cu content is than that of the grain boundary peak observed in pure aluminium. (2) When copper content reaches 0.5 wt %, P1 appears in measurements with descending temperatures. Eowever, this peak is lowered considerably when measured with ascending temperatures and another peak P2 appears around 360°C and is independent of frequency out varies with copper content, the way of changing temperatures, and ageing temperature and time. The elastic modulus dreps abruptly corresponding with the appearance of P2. (3) When copper content reaches 1.2 wt %, a peak P3 appears around 290°C when measured with descending temperatures. The behavior of P3 is similar to that of P2, except the elastic modulus rises insted of dropping corresponding with the appearance of P3. Experiments with specimens containing only a few bamboo boundaries and X-ray analysis show that the appearance of P2 and P3 is originaled respectively from the resolution and the precipitation of θ-phase along the grain boundaries. Experimente with Al-4 wt % that P'2 (430°C) and P'3 (410 °C) peaks associated with the re-solution and precipitation of θ-phase inside the grains proper appear together with peaks P2 and P3.