Hydrogen embrittlement or ordered alloy Fe3Al

The relationship between ordering in Fe3Al alloys and hydrogen embrittlement was investigated. Three sets of specimens with different heat treatments and structures (disordered, DO3 and imperfect B2) were tensile tested. Environmental effects were investigated in two conditions: vacuum of approx 6 x 10 exp --3 Pa and air; and air and H. Fracture surfaces were examined using SEM. It was shown that the Fe3Al intermetallic compound is susceptible to environmental embrittlement at ambient temperatures. The ordered compound was less susceptible to H embrittlement than the disordered one. The embrittlement was attributed to the reaction of water vapor with the Al constituent. The fracture mode did not change with varying test environments.