水素チャージ下でのモリブデンの引張性質

Abstract

Stress-relieved and recrystallized specimens of Mo and TZM are tensile tested at strain rates of 4×10−5 to 4×10−1/s at room temperature with and without cathodic hydrogen charging prior to and/or during tensile testing. In the recrystallized specimens tested at the lowest strain rate, a little decrease in the lower yield strength and the ultimate tensile strength, and significant decrease in the reduction in area and the fracture stress are found by the charging during tensile testing. At strain rates up to 4×10−2/s, these properties are still affected by the charging, though they recover with increasing strain rate, and the effects of hydrogen charging disappear at the strain rate of 4×10−1/s. Microscopic observation shows that cleavage fracture has occurred in the recrystallized specimens tested with the charging during tensile testing, even though the specimens are fairly ductile. Little effect of cathodic charging on the tensile properties of the stress-relieved specimens is found. The effect of cathodic current density on the tensile properties is also investigated.