Study on the effect of trace zirconium addition on the microstructural evolution in Cu-Zn-Al shape memory alloy

Present study concerns the effect of trace addition of Zr compared to Ti on microstructure formation of Cu-Zn-Al shape memory alloy due to isothermal ageing effect at temperatures between 50 and 300 °C and annealing at temperatures between 800 and 900 °C. In contrast to the presence of any visible precipitate density in the case of Zr added alloy, remarkable density of precipitate has been observed in the base- and Ti-added alloy at the peak aged condition. However, both Ti and Zr addition have significantly reduced the transformation temperatures in comparison to the base alloy. Moreover, it has been shown that trace addition of Zr helps in nucleation of favorable variants and reduced susceptibility to the solute drag effect.