Effects of cold rolling and annealing time on fatigue resistance of AA۵۰۵۲ aluminum alloy

In the present study, the influences of cold rolling and annealing time on the fatigue crack propagation behavior of AA۵۰۵۲ aluminum alloy were investigated. The alloy sheet was cold-rolled under different rolling reductions, i.e., ۰, ۱۵, ۳۰, and ۴۵%. ۴۵% as-rolled specimen was then annealed at ۳۷۰°C under different annealing times, i.e., for ۲, ۴, and ۶ h. The microstructure evolutions after the cold rolling and annealing treatments were also examined using optical microscopy whereas the fatigue crack propagation behavior was characterized by using a fatigue test. Results showed that severely elongated grains were observed with increasing the rolling reduction. The elongated microstructures were changed into equaxial structures due to recrystallization during annealing treatment. The fatigue life was decreased drastically by increasing the rolling reduction but increased significantly with increasing annealing time. The fatigue life of the alloy was reduced by ۹۳% when cold-rolled up to ۴۵%. On the other hand, the fatigue life of the ۴۵% rolled samples was increased significantly by ۴۱۲% when annealed at ۳۷۰ºC for ۶ h.

Keywords:

AA ۵۰۵۲ aluminum alloy , Cold rolling , Annealing , fatigue resistance