As-quenched microstructures of Cu3−xMnxAl alloys

In the as-quenched condition, the microstructure of the Cu2.9Mn0.1Al alloy was of D03 phase containing γ′1 martensite. This is similar to that reported by other workers in the Cu3Al alloy. However, the as-quenched microstructure of the Cu2.8Mn0.2Al or Cu2.7Mn0.3Al alloy were found to be of D03 phase containing extremely fine L-J precipitates, whereas for Cu2.6Mn0.4Al alloy, it was a mixture of (D03 + L21 + L-J) phases. These results are different from those proposed by Bouchard et al.