Abstract
The effect of pre-fatigue under high humidity environment on the quasi-static and impact tensile properties of7075 aluminum alloys was investigated. An impact tensile test was performed by means of the Split Hopkinson pressure bar method. Within the set of experiments, the flow stress was unaffected by the pre-fatigue deformation in the quasi-static and the impact test. It was shown that the elongation of the pre-fatigue specimen was slightly lower than that of the non-fatigue specimen in the both tests. The pre-fatigue specimen under high humidity environment had a lower elongation than under low humidity environment. It is thought that the decrease in elongation occurred by arrangement of the dislocations locally due to the pre-fatigue deformation under high humidity environment. Additionally, the elongation of the pre-fatigue specimen under high humidity environment in the quasi-static test decreased than that in the impact test. We infer that it is because the dislocation movement was enhanced by hydrogen during deformation in the quasi-static test.
