Stress-strain curves of commercially pure aluminum (JIS: A1100-H14) and super duralumin (JIS: A2024-T3) are determined in a wide range of strain rates under conditions of uniaxial strain. The plate impact testing with three in-material gauges is used to measure stress wavefronts and the UWSS is also used to derive various variables. The phase velocity of stress are determined on considering the effect of thickness of the gauges. For the low strain rate of ca. 1/10^4 [1/s] the stress-strain curves are determined under conditions of uniaxial stress by the universal testing machine combined with an extrapolation procedure. It is approximately shown that the stress is independent of strain-rate in a wide range under conditions of uniaxial strain for these light metals.