Effect of Pre-Fatigue Deformation under Humid Environment on Impact Tensile Properties in 7075 Aluminum Alloys

The effect of pre-fatigue deformation in a humid environment on the impact tensile properties of 7075 aluminum alloys was investigated. An impact tensile test of the pre-fatigue deformed specimens was performed by means of the Split Hopkinson pressure bar method. Within the author’s set of experiments, the flow stress was unaffected by the pre-fatigue deformation. On the other hand, it was shown that the ductility of the pre-fatigue specimen was slightly lower than that of the non-fatigue specimen in the impact test. Additionally, the pre-fatigue specimen in a high-humidity environment had a lower ductility than in a low-humidity environment. It is thought that the decrease in ductility occurred due to changes in the microstructure, such as dislocations caused by the presence of hydrogen in the specimen due to pre-fatigue deformation in a high-humidity environment.