Abstract
The early stages of spinodal decomposition in age hardening Cu-Ti alloys have been studied by electron microscopy. The alloys (1.55, 3.08 and 5.17 w/o Ti) decomposed on the quench from solutionizing temperatures into Ti enriched and Ti lean regions. Superlattice reflections, at 1 5 {420} m positions as well as 1 2 {210} m reflections were observed in the diffraction patterns of the as quenched 5.17 w/o Ti alloy. The alloys continued to decompose when aged at elevated temperatures. A sequence of microstructures was used to show that continuous phase separation, and hence spinodal decomposition, was the mechanism of decomposition. The metastable two phase structure which formed from the spinodal process was aligned and periodic from the start of the process. The Ti enriched phase was ordered, with the Dla(Ni 4Mo; 14/m) structure. Reversion experiments were performed to determine the position of the coherent metastable solvus. When aging treatments were performed near this solvus. heterogeneous nucleation of the metastable phase was observed.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call