Evaluation of hydrogen release routes on the microstructure of 6061 aluminum alloy surface by means of repetition in hydrogen microprint technique

Hydrogen microprint technique (HMT) was repeatedly applied to Al-Mg-Si base alloys without and with containing iron as an impurity element. A special jig was made to perform the repeated HMT, which can keep a constant loading using one specimen. By using this testing jig, we could verify the hydrogen emission behavior in the same microstructure of the Al-Mg-Si base alloys during deformation. It was shown that hydrogen atoms were released at grain boundaries in the early stage of the plastic deformation. When the applied strain was then increased, hydrogen atoms were released at the periphery of iron based intermetallic inclusions. Based on this, it was believed that hydrogen-trapping force by the inclusions was higher than that by grain boundary during deformation. © 2016 The Japan Institute of Light Metals.