Thermodynamical and Microstructural SME Study on CuAlNi and CuAlNiCo Shape Memory Alloys
Abstract
In this work, Cu-Al-Ni and Cu-Al-Ni-Co shape memory alloys were fabricated by arc melting process under vacuum. The fabricated samples were cut from the ingot into small pieces. After then, the samples homogenized and thermal and structural observations were made by DSC, TG/DTA and X-ray equipments. As the heating/cooling rate changed, the transformation temperatures were changed slightly. On the left side of heating parts of the cycles, the first downward endothermic peaks belong to the forward M→A transformation where β1’ converts to β1(L21) phase. Then, the α and γ2 precipitation phases emerge and disslolute and convert to a stable ordered β2 phase which can be understood from the downward eutectoid dissolution peaks.