Isothermal mechanical spectroscopy experiments were carried out on samples which had been water-quenched from 850C. Damping spectra were recorded, at increasing or decreasing temperatures, between 20 and 660C. At the same time, the microstructural evolution was studied using X-ray diffraction at room temperature in samples which had been subjected to similar annealing. Three relaxation processes were identified, which occurred in specific temperature ranges after well-defined thermal treatments. The first led to a small peak which had been associated with point-defect relaxation in the γ2 phase. A second peak, whose parameters were highly dependent upon annealing, could be attributed to dislocation motion. Finally, at temperatures above 600C, a large relaxation peak emerged and was probably linked to the presence of the ß phase.

Structural Evolution and Isothermal Mechanical Spectroscopy Analysis of a Cu-Al-Ni Alloy. V.Pelosin, A.Rivière: Philosophical Magazine A, 1999, 79[7], 1643-54