Effect of Al content on thermal stability, shape memory effect and mechanical properties of Cu–Al–Fe shape memory alloys

Cu–Al–Fe shape memory alloys are a new kind of smart materials with high phase transition temperature. However, poor thermal stability and poor shape memory effect limit the commercial application range. In this paper, the effect of Al content on microstructure, thermal stability, shape memory effect and mechanical properties of Cu–Al–Fe shape memory alloys was investigated systematically by changing Al content, so as to obtain the optimal composition ratio for better commercial application. The results show that in the as-cast state, the microstructure is a mixture of (Cu) phase, β′ martensite and Fe(Cu, Al) phase with Al content of 11 mass%, and a mixture of β′ martensite and Fe(Cu, Al) phase with Al content of 12 mass% and 13 mass%. After quenching, β′ martensite exists in all alloys, while (Cu) phase and Fe(Cu, Al) phase disappear, and γ′ martensite also exists at Al content of 13 mass%. The shape memory alloy effect of as-cast alloy is enhanced with the increase of Al content, while the shape memory effect of quenched alloy increases first and then decreases. Among them, Cu 82 Al 13 Fe 5 has the best shape memory effect, the recovery ratio reaches 84.38%, and it also has the best thermal stability.