en Research Paper Research Paper The hot deformation behavior of the heat-treated AA6061 and AA 6063 aluminum alloys by T6-1, T6-2 artificial aging treatment, and O annealing treatment were studied by compression testing over a temperature range of 350&ndash;550 <img alt="" chromakey="white" src="file:///C:/Users/hr_re/AppData/Local/Temp/msohtmlclip1/01/clip_image001.png" > &nbsp;and strain rates of 0.005-0.1 s^-1. It was observed that the flow stresses of the studied aluminum alloys treated by the T6-1 and T6-2 heat treatments were significantly higher than those of the O annealing treatment. Moreover, the stress-strain curves of the heat-treated alloys by the T6-1, T6-2, and O heat treatments demonstrated significant softening during deformation at the lowest strain rate under any of the deformation conditions. For several strains, the activation energy of hot deformation was specified and obtained to vary significantly with strain for the heat-treated alloys by the T6-1 and T6-2 treatments. The stress-strain data calculated from a linear equation, with strain-dependent parameters, shows a great fit with the experimental data for the heat-treated aluminum alloys. Hot deformation,AA6061,AA6063,Flow stress,Heat treatment,Aging,Annealing. 1 17 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-3037-1&slc_lang=en&sid=1 Masumeh Mohammadi masumehmohamadi70@gmail.com 1800319475328460014666 1800319475328460014666 No School of Mechanical Engineering, Arak University of Technology, Arak, Iran. Hamidreza Rezaei Ashtiani hr_rezaei@arakut.ac.ir 1800319475328460014667 1800319475328460014667 Yes School of Mechanical Engineering, Arak University of Technology, Arak, Iran