New insights into the effects of solidification process on the thermodynamic parameters and mechanical properties of CuAlBeNbNi shape memory alloy

Abstract

In this work, the influence of the processes of unidirectional solidification and squeeze casting in microstructure, thermodynamic parameters and mechanical properties of CuAlBeNbNi shape memory alloy (SMA) was investigated. The results show that the unidirectional solidification process causes an increase in phase transformation temperatures and ductility, improves fracture toughness and reduces stress-induced martensite, residual stress and dissipated energy after load-unload tensile test of the CuAlBeNbNi alloy. The squeeze casting process, on the other hand, causes an increase in the density of grain boundaries, increasing the stress-induced martensite and the elastic energy of the direct martensitic transformation, while decreasing the impact toughness, increasing the residual deformation, the residual stress and the dissipated energy after the tensile cycle tests. These results indicate that the processes of unidirectional solidification and squeeze casting offer an alternative method to modify the thermodynamic parameters, mechanical properties, and microstructural properties of the CuAlBeNbNi SMA while keeping the composition constant. This study aims to fill the knowledge gap regarding the impact of solidification processes on the properties of Cu-based SMAs, specifically investigating CuAlBeNbNi SMAs.

Keywords

• Cu-based SMA
• Unidirectional solidification
• Squeeze casting
• Microstructural evolution
• Phase transformation