Toughness-strength relations in the overaged 7449 Al-Based alloy

Kamp, N., Sinclair, I. and Starink, M.J. (2002) Toughness-strength relations in the overaged 7449 Al-Based alloy. Metallurgical and Materials Transactions A, 33A, (4), 1125-1136.


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This article examines the relationship between plane strain fracture toughness, KIc, the tensile properties, and the microstructure of the overaged 7449 aluminum-plate alloy, and compares them to the 7150 alloy. The 7449 alloy has a higher content of η′/η precipitates; and, the 7150 alloy contains a greater amount of coarse intermetallic particles, as it contains an appreciable amount of coarse S phase (Al2CuMg), which is largely absent in the 7449 alloy. The toughness of the alloys shows an increase on overaging, and the 7449 alloy shows a reasonably linear toughness—yield strength relation on extended overaging. Several mechanisms of failure occur: coarse voiding at intermetallics and a combined intergranular/transgranular shear fracture mode, with the former becoming more important as overaging progresses. Drawbacks of existing models for toughness are discussed, and a new model for plane strain fracture toughness, based on the microstructurally dependent work-hardening factor, KA, introduced in Ashby's theory of work hardening, is developed. This model predicts a linear relation between KIc and K0.85A/σ0.35ys, where σys is the yield strength, which is consistent with the experimental data.

Item Type: Article
Related URLs:
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TL Motor vehicles. Aeronautics. Astronautics
T Technology > TN Mining engineering. Metallurgy
Divisions: University Structure - Pre August 2011 > School of Engineering Sciences
University Structure - Pre August 2011 > School of Engineering Sciences > Engineering Materials & Surface Engineering
ePrint ID: 21984
Date Deposited: 16 Mar 2006
Last Modified: 27 Mar 2014 18:11
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