Effects of Homogenization Treatment on Dispersoid Characteristics and Recrystallization Behavior in an Al-Zn-Mg-Cu-Zr Alloy

Abstract

In the present research, a comprehensive study on the effect of the homogenization treatment on the characteristics of dispersoid and recrystallization behavior in an Al-Zn-Mg-Cu-Zr alloy has been conducted by means of optical micrography, scanning electron micrography and transmission electron micrography. The influence of three process parameters of the homogenization treatment, first stage holding temperature, holding time and heating rate, on the dispersoid characteristics has been throughly studied. The result shows that holding at 400°C for sufficient time is highly beneficial for obtaining fine and uniformly distributed Al3Zr particles. Compared with the high heating rate treatment, the slow one apparently leads to significantly smaller Al3Zr dispersoids, the dimension of the dispersoids decreases from 35 nm to 22 nm, and the number density of Al3Zr particle in the center of the grains increases from 13/μm2 to 35/μm2. The percentage of recrystallized grains of the alloy is found to be affected by dispersoid distribution.