Precipitation behaviors of cubic and tetragonal Zr-rich phase in Al-(Si-)Zr alloys

The precipitation behaviors of Zr-rich phase in binary Al-0.5Zr and ternary Al-3Si-0.5Zr alloys were investigated by high resolution transmission electron microscopy and atom probe. After the alloys were aged at 525 °C for 24 h, the precipitates in Al-0.5Zr alloy are identified as L12-ZrAl3, performing a coherent relationship with the Al matrix. While in Al-3Si-0.5Zr alloy, the precipitates are Si-containing D023-Zr(Al,Si)3, which has an approximate 90° reversed cube-on-cube orientation relationship with Al. It is regarded that Si accelerates the precipitation of D023-Zr(Al,Si)3.