Effect of Bi addition on precipitation and dissolution in Cu–9at% In and Cu–5at% Sb alloys
The effect of Bi addition on precipitation and dissolution, in Cu–9at% In and Cu–5at% Sb supersaturated solid solutions, has been studied by several complementary techniques. Differential Dilatometry and Differential Scanning Calorimetry permit only the analysis of the δ phase dissolution kinetic in sufficiently aged samples. Delayed spheroidization due to Bi segregation around the precipitated lamellae, observed by Transmission Electron Microscopies in the first alloy, gives a residual interfacial energy leading to accelerated δ phase dissolution with decreased activation energy. Kinetics parameters evolution indicates a progressive δ phase continuous dissolution which makes available a small chemical driving force at high temperatures and leads to an increasing activation energy during dissolution. However, Bi dispersed particles in the second alloy haven’t effect on the dissolution but they cause a contraction above 833 K. Kinetics parameters evolution indicates rapid δ phase dissolution that shifted to high temperatures where an important chemical driving force for solution treatment is available. It leads to almost constant activation energy.
KeywordsPrecipitation Segregation Dissolution Calorimetry Kinetics activation energy
The authors like to express their sincere thanks to Ellen Baken and Anna Carlsson from TEM Applications Laboratory of NanoPort FEI COMPANY (Netherlands) and Guillaume Brunetti, TEM/FIB Application and Marketing Engineer, JEOL (Europe), for assistance with the TEM and SEM analysis.
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