Stress Corrosion Cracking of Wrought and P/M High Strength Aluminum Alloys.
Annual technical rept. 1 Jan-31 Dec 82,
CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF METALLURGY AND MATERIALS SCIENCE
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The combined results of the first two years of the program are presented, with emphasis on the stress corrosion cracking and hydrogen embrittlement of the PM X-7090 Al alloy. More complete results on 7075 are also given. In particular, the role of temper and loading mode and susceptibility were examined for three test methods--time to failure of notched round bar specimens in a brine solution straining electrode tests on notched round specimens under cathodic charging and tensile tests on hydrogen pre-charged notched round specimens. Another study examined the role of concurrent recovery processes during slow strain rate testing of cathodically charged 7075 and established that hydrogen outgassing is not a factory in the recovery, which instead is due to internal rearrangement of hydrogen to various trap sites. Also, a successful measurement of hydrogen diffusivity in aluminum has been made at room temperature using sandwich type specimens. The value obtained, about 10 to the -15th power cm sqs is one of the first successful measurements of this type.
- Properties of Metals and Alloys