Effect of Ta addition on microstructures, mechanical and damping properties of Cu–Al–Mn–Ti alloy

Cu–Al–Mn–Ti–xTa alloys (x = 0, 1, 2, 3, wt.%) prepared by spark plasma sintering were investigated for the effect of Ta content on the microstructure, mechanical and damping properties. The microstructure and phase composition indicate that the alloy is mainly composed of β′1 martensite, γ′1 martensite, Ti-rich and Ta-rich phase. As the Ta content increases, the grain size of the alloy first decreases and then increases. The reverse trend was observed for hardness, tensile and compressive strength. The hardness, tensile strength and compressive strength increased by 18.2%, 44.9% and 28%, respectively, when the Ta content was 1 wt.% compared to the alloy without Ta element. The presence of martensite provides the alloy with promising damping properties. Meanwhile, the formation of the second phase has a two-sided effect on the damping characteristics. That is, the increase in grain boundaries provides more interfaces for energy dissipation, but the increased compressive stress between the interfaces also hinders the movement of the interfaces. Excellent damping performance is demonstrated with the addition of 1 wt.% of Ta element. The peak values of damping capacity at room temperature and at about 580 °C reached 0.026 and 0.19, respectively. The results confirm that the addition of Ta elements is achievable to obtain Cu–Al–Mn–Ti alloys with both high mechanical and damping properties.