With recent development in the automotive and aerospace industries, the lightweight, yet inexpensive aluminum alloys are of great demand in industrial applications. In this paper, considering the limited applications in non-superplastic materials, two typical alloys of AA5083 and AA6061 were investigated and compared during high temperature tensile tests to study their formability. The results of tensile tests and microstructures were shown, which indicated the deformation properties under different conditions. Both alloys exhibited relatively weak strain hardening effects especially at relatively lower strain rates. Furthermore, the highest strain rate sensitivity index (m value) was obtained, and the peak of percent elongation-to-failure also coincided with the ranges of highest m value. The flow stress coupled with the dynamic grain growth was related with the temperatures and strain rates. The grains appeared to be coarser in the deformed samples. Cavitation and recrystallization have also been found as a result of strain rate and temperature. © 2009 Elsevier Ltd.