| Effects of cathodic hydrogen charging on tensile properties of Al 8090 alloy were examined as functions of charging time, strain rate, specimen orientation and aging condition. Round bar specimens were cathodically charged in 0.1N HCl solution under an applied potential of -1800mV vs. SCE for 12 and 24 hours, respectively. It was found that Al 8090 alloy showed a substantial decrease in tensile elongation with hydrogen charging, while the decrease in tensile elongation was linearly proportional to (charging time)^(1/2), suggesting that Al 8090 alloy is susceptible to hydrogen embrittlement. SEM fractographic examinations demonstrated that fracture mode was intergranular dimpled rupture, regardless of cathodic hydrogen charging. Hydrogen charging, however, appeared to reduce the plasticity around the dimples on the intergranularly fractured surface of Al 8090 alloy. T-oriented Al 8090 alloy specimens showed higher sensitivity to hydrogen embrittlement, indicating that grain boundary played an important role in hydrogen-assisted deformation (and fracture) for Al 8090 alloy. Overaged Al 8090 alloy specimen showed slightly higher sensitivity to hydrogen embrittlement than peakaged counterpart, suggesting that hydrogen charging further reduced the plasticity in overaged condition. |
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