Effect of solid solution state of zirconium and Al3Zr (L12) precipitates on the recrystallization behavior of Al‐0.2 wt.%Zr alloy.

Effect of homogenization annealing on the existence form of zirconium in Al‐0.2wt.%Zr alloy and effect of various existence form of zirconium on the recrystallization behavior of Al‐0.2wt.%Zr cold‐rolled (total deformation is 92.8 %) sheet are studied. The results show that large numbers of nearly spherical Al3Zr (L12) nanoparticles precipitated from aluminum matrix after homogenizing at 475 °C for 24 h. Moreover, due to the precipitation of Al3Zr particles, the hardness and electrical conductivity of the as‐cast Al‐0.2wt.%Zr alloy is increased from 25.1±0.5 HV 3 and 54.0±0.2 %IACS to 28.6±0.7 HV 3 and 56.2±0.1 %IACS, respectively. Hence, zirconium exists as solid solution state in the as‐cast Al‐0.2wt.%Zr alloy and metastable Al3Zr phase in the homogenized alloy. Moreover, the recrystallization temperature of the pure aluminum without addition of zirconium is 300 °C, while the recrystallization temperature of the Al‐0.2wt.%Zr alloy without and with homogenization is about 350 °C and 400 °C, respectively. Obviously, the solid solution state of zirconium has certain effect on retarding the recrystallization of aluminum alloy, while the nanometer Al3Zr particles can inhibit the recrystallization of aluminum alloy effectively and increase the recrystallization temperature remarkably. [ABSTRACT FROM AUTHOR]