The Evolution of Second-Phase Particles in 6111 Aluminum Alloy Processed by Hot and Cold Rolling

The evolution of coarse Al_9.9Fe_2.65Ni_1.45 phase, spherical Al₁₂(Mn,Fe)₃Si phase and rod-like Q phase in a 6111 aluminum alloy during hot and cold rolling deformation processes was systematically investigated in this work. The results showed that the coarse Al_9.9Fe_2.65Ni_1.45 particles are mainly distributed at the grain boundaries, accompanied by the co-formation of Al₁₂(Fe,Mn)₃Si phase and Mg₂Si phase, while the spherical Al₁₂(Mn,Fe)₃Si particles are mainly distributed in the grain interiors. Hot rolling has little effects on the size and distribution of both phases, but cold deformation can severely decrease the size of the particles by breaking the particles into small pieces. In addition, the temperature of 450 °C is not high enough for the dissolution of Q phase in the Al matrix, but the Q particles can be broken into small pieces due to the stress concentration during both hot and cold rolling deformation. In addition, the influences of phase evolution, dislocations and recrystallization on the mechanical properties evolution were also discussed.