Effect of high strain rate deformation on hydrogen desorption behavior of 6061 and 7075 aluminum alloys

Abstract

Hydrogen desorption behavior in 6061 and 7075 aluminum alloys was studied by means of thermal desorption analysis using a semiconductor hydrogen sensor in the gas chromatograph. Effect of high strain rate deformation (10 5 s 1) on the hydrogen trapping state in the alloys was examined in particular. It was found that hydrogen atoms were released at lower temperatures when both alloys were plastically deformed. The tendency was more obvious in the 6061 alloys deformed with a high strain rate. In comparison with the previous reports, the difference of the hydrogen desorption behavior in the case between high speed and low speed deformation would be related to the difference of the hydrogen trapping effects by the different type of lattice defects.

Evaluation of Hydrogen Embrittlement of Electroless Ni–P Plated 6061-T6 Aluminum Alloy by Three-Point Bending and Rotating Bending Fatigue Tests

“…For the un-treated specimen, the hydrogen release up to 420°C was slight, and the peak from 420°C seemed to correspond to desorption of molecular hydrogen strongly trapped in micropores inside the alloy. 8,9) On the other hand, hydrogen release was observed from all plated specimens, which confirms that hydrogen was taken up by the plating.…”

“…The peak at approximately 140°C was attributed to hydrogen in the interstitial space of aluminum. 8) The hydrogen release peak based on vacancy-hydrogen clusters at 190-240°C 8) suggests that vacancy-hydrogen clusters were also present. The hydrogen release in the zinc-plated specimen was smaller than that in the Ni-P-plated specimens.…”

Effect of Electroless Ni–P Plating on Rotary Bending Fatigue Strength of A2017-T4 Aluminum Alloy

“…5 are consistent with the results of the high-phosphorus-type plated specimen having a large amount of hydrogen in the film. Next, another peak based on vacancy-hydrogen clusters in aluminum appears between 190 and 240°C, 16) suggesting the existence of these two peaks in addition to the peak around 140°C in the high phosphorus-type plated specimen. The hydrogen release peak, indicating the existence of vacancy-hydrogen clusters, which does not appear in the low-phosphorus-type plated specimen, is considered to be heavily involved in the reduction of fatigue strength.…”

“…The peak appearing at approximately 140°C was shown to be hydrogen existing in the interstitial space of aluminum. 16) Comparing the two peaks, the peak width of the high-phosphorus-type plated specimen is much wider than that of the low-phosphorus-type plated specimen, which suggests that the high-phosphorus-type plated specimen has another peak overlapping the peak at approximately 140°C. It has been shown that the hydrogen release peak from the NiP-plating film appears at approximately 80°C.…”

“…The hydrogen release peak beginning at 480°C is thought to correspond to the release of molecular hydrogen, which is strongly trapped in the micropores inside the alloy. 16,17) Note that this peak does not appear for the double-zincated and plated specimens. This may be due to the fact that the displacement-deposited zinc film and NiP-plated film prevented hydrogen release and shifted the peak to a higher temperature above 500°C.…”