The apparition of a new reaction at lower temperature in equiatomic CuAu alloy

Abstract

Recently a lot of interest has been devoted to the study of order–disorder transitions in different materials. Although the equiatomic CuAu alloy represents a classical model of this type of transformation, it still receives considerable attention because many questions about phase transitions are still raised according to its equilibrium diagram. In this context, the present paper carries a new result observed in CuAu alloy consisting of a new anomaly observed on differential scanning calorimetry (DSC) curves at low temperature and new peaks in X-ray diffraction (XRD) spectra. For that, we will try to give an explanation of the origin of this new reaction, with the help of other techniques as electrical resistivity and microhardness measurements. The kinetic behaviour of this new reaction has been also studied by anisothermal analysis during DSC tests to estimate the kinetics parameters as activation energy E _act and Avrami exponent n.

Keywords:

• DSC
• X-ray diffraction
• copper alloys
• HRTEM

Acknowledgements

The authors like to express their sincere thanks to Régis Ravelle–Chapuis and JEOL (EUROPE) SAS for assistance with the HRTEM analysis.