Abstract
In order to elucidate the hydrogen embrittlement of the aluminum alloys, it would be worthwhile to detect hydrogen evolution during tensile deformation and fracture. In this study, the hydrogen evolution behavior during tensile deformation and fracture in T6-tempered 6061 and 7075 aluminum alloys was detected by means of a testing machine equipped with a quadrupole mass spectrometer installed in an ultra-high vacuum chamber. Furthermore, local hydrogen evolution behavior of the both alloys was visualized with a hydrogen microprint technique. It is clarified that the hydrogen evolution started at the stage of elastic deformation in the both alloys. However, the amount of hydrogen evolved at the elastic deformation in 7075 alloys was much higher than that in 6061 alloys. This suggested that the hydrogen diffusion was promoted due to the existence of the stress field caused by second phase inclusions (A17Cu2Fe), since the 7075 alloy has higher proof stress than the 6061 alloy. In addition, the higher amount of hydrogen was evolved at the beginning of plastic deformation particularly in the 7075 alloy. This indicates that primarily dissolved hydrogen was transported to the surface of specimen with the aid of mobile dislocations.
