Effect of precipitation during parent phase aging on the microstructure and properties of a refined CuAlMn shape memory alloy

Effect of precipitation during parent phase aging on the microstructure and properties of a CuAlMn shape memory alloy (SMA) refined by CuZr inoculant was investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), Vickers hardness tester (VHT) and dynamic mechanical analyzer (DMA). It was found that after aging in parent phase at relatively low temperatures, such as 500 °C, the precipitation of α phase and γ2 phase in the CuAlMn SMA was uncontrollable because it was highly sensitive to aging time. While the aging in the temperature range of 530-620 °C could give rise to controllable precipitation, and by optimizing the microstructures in this way, the hardness and damping of the CuAlMn SMA could be significantly improved. Therefore, proper aging treatment is a convenient and feasible method to control the microstructure and properties of the Cu-based SMAs.