In sıtu Temperature Study of the Li0 & A1 Transformation in Cu50Aus50-xPdx Alloys by Electron Microscopy

Abstract

In the ternary Au-Cu-Pd system, in situ temperature observations have been performed in transmission electron microscopy on a number of compositions Cu 50 Au 50−x Pd x (x = 3, 7.5, 10 and 15). All samples undergo a reversible order-disorder transition L1 0 ⇄ A1 at a temperature T t . The crystallographic and morphological aspects of the transition are examined. The «in situ» reversible transition temperatures T t are determined (with a marked hysteresis) for all compositions and compared with the values measured by differential calorimetry and those obtained from usual long time annealings. In addition, quenched Al and as-rolled samples undergo the irreversible transformation Al → L1 0 with increasing temperature at about T t (°C)/2