412 アルミニウム合金における水素侵入挙動に及ぼす晶出第二相の影響(OS4-(3)オーガナイズドセッション《材料と組織》)

Abstract

The use of hydrogen as a clean energy is being highlighted particularly in terms of the prevention of global warming. In this relation, hydrogen fuel cell vehicles have been developed, where aluminum is used as the liner of cylinders for compressed hydrogen gas. For the safety of the vehicle, for the prevention of hydrogen embrittlement of the liner, hydrogen behavior is required to be elucidated. In this study, hydrogen microprint technique, HMPT, has been applied to a series of aluminum alloy containing a single kind of constituent particles, to elucidate the invasion behavior of hydrogen affected by constituent particles as this effect is suggested in some previous reports, particularly in 7075 aluminum alloys. Several Al-Cu-Fe alloys with different fraction of Cu_2FeAl_7 phase, the mail constituent phase in 7075 alloys, have been laboratory-produced into a sheet of about 1mm thickness. Hydrogen atoms permeated from one surface at hydrogen gas of 0.3MPa to the other surface covered with photographic emulsion for HMPT have been observed as silver particles. In Al-11mass%Cu-5mass%Fe alloy, since the hydrogen atoms have been detected only on the Cu_2FeAl_7 particles, hydrogen emission site is confirmed to be only this phase as in the 7075 alloy. However, the emission amount is markedly smaller than in the 7075 alloy, which implies that the other phase consisting of the alloying elements such as Zn and Mg also plays an important role in the process of hydrogen invasion and diffusion.