Exploring the Effect of Carbon Addition on the Mechanical and Thermal Behavior of Cu-11Al-5Ni Shape Memory Alloy
摘要
Cu-Al-Ni alloys are widely used in industrial applications such as those in the automotive and aerospace sectors. The incorporation of carbon into Cu-Al-Ni alloys offers a promising solution for overcoming the strength–ductility trade-off. This research aims to improve the microstructure, mechanical properties, and thermal properties of Cu-11Al-5Ni alloys through 0.8 wt.% C and 1 wt.% C additions. Using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS), the microstructure of the prepared samples was examined to determine their phase composition. The results revealed that the primary γ2-Al4Cu9 intermetallic compound (IMC) phase formed in all the as-cast alloys. Additionally, the β-AlCu2 martensite phase was detected, with no secondary IMC phases observed. The slow cooling rate was the main reason for the transformation of the β-AlCu2 martensite phase to the γ2-Al4Cu9 IMC phase. Tensile tests showed that the addition of 0.8 wt.% and 1.5 wt.% carbon improved the ultimate tensile strength by 9% and 10% and uniform elongation by 19.2% and 37.4%, respectively. Notably, a significant synergy of high strength and ductility was observed, indicating excellent service performance of the alloys. Differential scanning calorimetry (DSC) measurements revealed a decrease in transformation temperatures as carbon content increased. These findings are expected to benefit industrial applications.