Masahiko Ogura

THERMAL BEHAVIOR OF HYDROGEN IN HELIUM-IMPLANTED HIGH-PURITY SUS316L

Abstract We have studied the effects of helium incorporation on trap-sites of hydrogen in high-purity stainless steel SUS316L. We implanted 10 and 30 keV He ions into high-purity SUS316L samples with several doses ranging from 3 × 10 15 to 1 × 10 17 /cm 2 and then 30 keV hydrogen ions with a dose of 1 × 10 17 /cm 2 at a temperature of 300 K, and then observed depth profiles and thermal behavior of hydrogen in the samples by means of the elastic recoil detection (ERD) method. It was found that hydrogen implanted into the high-purity SUS316L is chemically absorbed in helium cavities.

The annealing behavior of hydrogen implanted into Al-1.5 at.% Si alloy

We have studied effects of added elements as well as defects on trap-sites of hydrogen in metals. For the purpose, we observed depth profiles and thermal behaviors of hydrogen implanted into Al-1.5 at.% Si alloy samples in an implantation-temperature range of liquid nitrogen temperature (LNT) to 373 K at different doses. The results were compared with those for pure aluminum samples. It was found that hydrogen is trapped as molecules in grain boundaries of Al/Si.

TRAPPING OF HYDROGEN IN SILICON-IMPLANTED ALUMINUM

Abstract We have studied the effects of added silicon on trap-sites of hydrogen in aluminum. For this purpose, we implanted 78-keV silicon ions into pure aluminum specimens, and observed depth profiles and thermal behavior of hydrogen implanted into the samples at liquid nitrogen (LNT) and room temperatures (RT). It was found that for the RT implantation, hydrogen trapped in the AlSi alloy layer forms H2 bubbles in grain boundaries of Al Si .

Effect of implanted silicon on hydrogen behavior in aluminum and nickel

Abstract We have used elastic recoil detection (ERD) to study the behavior of hydrogen in Si-implanted Al and Ni samples, with a particular emphasis on the effect of the grain boundaries formed by implanting additive elements on hydrogen precipitation. From the measured H depth profiles and their thermal behavior, it is shown that the presence of an Al–Si layer in the near-surface region obstructs the annihilation of vacancies formed by hydrogen implantation in the pure Al region. In the case of Si-implanted Ni samples, hydrogen hardly precipitates except for the case of annealing procedure done at a relatively low temperature at which silicides are not formed but vacancies produced by the Si implantation are removed from the samples. These hydrogen trap sites were identified and the observed facts are explained well by taking into account the interface formed by the Si implantation.

The dose effect of silicon implantation on hydrogen trapping in aluminum

Abstract We have studied the dose effect of silicon as an added element on the trapping of hydrogen in aluminum. For this purpose, we implanted 78 or 150 keV silicon ions into aluminum specimens with doses of 3 × 1015–3 × 1017Si/cm2 and successively 30 keV hydrogen ions with a dose of 3 × 1016H/cm2 at 300 K. After the hydrogen implantation, the depth profiles and thermal behaviors of hydrogen in the samples were measured by means of an elastic recoil detection (ERD) method. It was found that the silicon element implanted into aluminum is supersaturated even at 5 at.% and drastically affects the thermal behavior of hydrogen, depending on the dose.

Trapping of hydrogen in aluminum- and silicon-irradiated aluminum

We have studied effects of the damage caused by pre-irradiation of heavy ions on the trap sites of hydrogen implanted into aluminum. For this purpose, aluminum samples were first irradiated with 40-keV Al2, 30- and 123-keV Si ions at a temperature of 125 K. Then, 30-keV H ions were implanted into the pre-irradiated samples after keeping them at 125 K for different time intervals in order to partially recover the irradiation damage. Depth profiles and the thermal behavior of hydrogen were observed by an elastic recoil detection (ERD) method. The obtained results were compared with those for non-irradiated pure aluminum samples. It was found that the disorder caused by heavy-ion irradiation and vacancies surviving without annihilation influence the trapping of hydrogen in the temperature range of stage-II recovery.