TY - JOUR
T1 - Effect of wet environment on hardness and yield stress of B2 Fe-Al alloys
AU - Hosoda, Hideki
AU - Yoshimi, Kyosuke
AU - Inoue, Kanryu
AU - Hanada, Shuji
PY - 1998/12/31
Y1 - 1998/12/31
N2 - Effects of wet environment on hardness and yield stress of B2 Fe-Al alloys at room temperature (RT) were investigated. First, change in micro Vickers hardness was measured for annealed Fe-18 mol% Al and Fe-25 mol% Al alloys as a function of the duration spent in: (1) distilled water at RT after a drying treatment; and (2) dry air at 427 K after a wet treatment. An age-hardening-like phenomenon appears for the former case and an age-softening-like phenomenon takes place for the latter case. Such changes in hardness caused by environmental treatments are reversible. Second, room-temperature yield stress and hardness were measured for annealed and vacancy-introduced Fe-44 mol% Al single-crystal alloys, where specimens were kept in various environments for a long time in order to achieve their equilibrium states. It is concluded that, with absorbing hydrogen, annealed Fe-Al alloys are hardened and vacancy-introduced Fe-Al alloys are softened, A new method is proposed for estimating the diffusivity of a solute. Hydrogen diffusivity (DH) at RT is estimated to be around 10-11 m2/s for Fe18Al and 10-12 m2/s for Fe25Al, suggesting that DH is lowered with increasing Al content in Fe-Al alloys.
AB - Effects of wet environment on hardness and yield stress of B2 Fe-Al alloys at room temperature (RT) were investigated. First, change in micro Vickers hardness was measured for annealed Fe-18 mol% Al and Fe-25 mol% Al alloys as a function of the duration spent in: (1) distilled water at RT after a drying treatment; and (2) dry air at 427 K after a wet treatment. An age-hardening-like phenomenon appears for the former case and an age-softening-like phenomenon takes place for the latter case. Such changes in hardness caused by environmental treatments are reversible. Second, room-temperature yield stress and hardness were measured for annealed and vacancy-introduced Fe-44 mol% Al single-crystal alloys, where specimens were kept in various environments for a long time in order to achieve their equilibrium states. It is concluded that, with absorbing hydrogen, annealed Fe-Al alloys are hardened and vacancy-introduced Fe-Al alloys are softened, A new method is proposed for estimating the diffusivity of a solute. Hydrogen diffusivity (DH) at RT is estimated to be around 10-11 m2/s for Fe18Al and 10-12 m2/s for Fe25Al, suggesting that DH is lowered with increasing Al content in Fe-Al alloys.
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U2 - 10.1016/s0921-5093(98)00926-5
DO - 10.1016/s0921-5093(98)00926-5
M3 - Article
AN - SCOPUS:0003378243
SN - 0921-5093
VL - 258
SP - 135
EP - 145
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
IS - 1-2
ER -