Determination of the Thermodynamic SME Parameters and Related Structure of Arc Melted CuAlNiV HTSMA

Abstract

Low cost Cu-based shape memory alloys (SMAs) have been regarded as potential alternative to the superior NiTi SMAs that are expensive and the most commercial SMAs. Hence, by many researchers have been interested with Cu-based SMAs and studied to develope them and improve their shape memory and other properties. In this work, the quaternary CuAlNiV high-temperature SMA (HTSMA) was manufactured by arc melting technique. Solution treatment for homogenization CuAlNiV alloy and post quenching in iced-brine water were carried out to form the martensite phase (shape memory effect property) in the alloy. Differential calorimetry (DSC and DTA) and X-ray diffraction (XRD) characterization measurements were carried out to detect the thermal and structural shape memory effect properties of the CuAlNiV alloy. The differential scanning calorimetry (DSC) results revealed the powerful reversible martensitic phase transformation peaks in a temperature region above 100 °C, indicating the HTSMA property of the alloy. Many important thermodynamic parameters related to these martensitic transformation reactions of the CuAlNiV HTSMA were determined by making the peak analyses of these transformation peaks. The differential thermal calorimetry (DTA) test result, also showed the martensitic transformation peaks of the alloy, revealed the multiple phase transitions of β'1→ β1(L2₁)→B2→A2 which occurred consecutively during heating the alloy in the temperature region between room temperature and a high temperature (900 °C). The XRD pattern of the alloy obtained by using CuKα radiation at room temperature revealed the presence of the formed martensite phases in the alloy. All results showed that the fabricated CuAlNiV memory alloy can be utilized as an HTSMA in the relevant SMA applications.