Closure-affected fatigue crack propagation behaviors of powder metallurgy-processed Al-Li alloys in various environments
- Gyeongsang National Univ., Chinju (Korea, Republic of). Div. of Materials Science and Engineering
- Seoul National Univ. (Korea, Republic of). Dept. of Metallurgical Engineering
The environment-affected fatigue crack propagation (FCP) behavior of rapid solidification-processed (RSP) Al-2.6Li-1.0Cu-0.5Mg-0.5Zr (RSP 644-B) and mechanically alloyed (MA) Al-4.0Mg-1.5Li-1.1C-0.8O{sub 2} (MA 905-XL) were examined in air, in vacuum, and in an aqueous 3.5 pct NaCl solution at R = 0.1 and a sinusoidal frequency of 20 Hz. The emphasis was placed on the effect of environment-sensitive crack closure on the FCP behavior of the fine-grain-sized powder metallurgy (P/M)-processed Al-Li alloys. The present study suggests that closure is extremely sensitive to environmental factors and significantly alters the environment-affected da/dN-{Delta}K relationships for both alloys. In the submicron grain-sized MA 905-XL, for example, increased corrosion product-induced closure in aqueous NaCl appeared to overwhelm the detrimental environmental effects in low- and intermediate-{Delta}K regimes. The environment-sensitive closure contribution alone, however, cannot completely explain the FCP behavior of P/M-processed Al-Li alloys. The intrinsic environmental effects also need to be considered for further understanding of this behavior.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 691382
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 30, Issue 8; Other Information: PBD: Aug 1999
- Country of Publication:
- United States
- Language:
- English
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