Precipitation in a CuCrZrMg alloy during aging

Abstract

The precipitation processes in a Cu-0.69Cr-0.10Zr-0.02Mg alloy aged at 450 C and 550 C have been investigated by transmission electron microscopy and high resolution transmission electron microscopy. The precipitation sequence in this alloy aged at 450 C is: supersaturated solid solution → Guinier-Preston zone (fcc Cr-rich phase) → ordered fcc Cr-rich phase → ordered bcc Cr-rich phase. The precipitation sequence in this alloy aged at 550 C is: supersaturated solid solution → ordered fcc Cr-rich phase → ordered bcc Cr-rich phase. In the evolution of decomposition, the orientation relationship between the precipitates and the Cu matrix changes from cube-on-cube to Nishiyama-Wassermann orientation. The ordering of Cr-rich precipitates facilitates the formation of the bcc precipitates and promotes the development of Nishiyama-Wassermann orientation. © 2013 Elsevier Inc.