Kinetics of isothermal decomposition in polycrystalline β CuAlBe alloys

The kinetics of the microstructural evolution of the metastable β phase during isothermal aging in a Cu-22.60Al-3.26Be (at%) polycrystalline shape memory alloy has been studied by electrical resistivity measurements and microscopical examinations. With an isothermal treatment at around 820 K, the alloy rapidly decomposes into γ2 phase with dendritic morphology, while between 670 K and 760 K the formation of α′ phase followed by the eutectoid decomposition is observed. A TTT diagram was estimated and the stability boundaries of the β phase in the studied alloy were compared with those of other Cu-based shape memory alloys.