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Microstructure Characterization and Stress Corrosion Evaluation of Autogenous and Hybrid Friction Stir Welded Al-Cu-Li 2195 AlloyFriction stir welding process is being evaluated for application on the Al-Cu-Li 2195 Super-Light Weight External Tank of the Space Transportation System. In the present investigation Al-Cu-Li 2195 plates were joined by autogenous friction stir welding (FSW) and hybrid FSW (friction stir welding over existing variable polarity plasma arc weld). Optical microscopy and transmission electron microscopy (TEM) were utilized to characterize microstructures of the weldments processed by both welding methods. TEM observations of autogenous FSW coupons in the center section of the dynamically-recrystallized zone showed an equiaxed recrystallized microstructure with an average grain size of approx. 3.8 microns. No T(sub 1), precipitates were present in the above-mentioned zone. Instead, T(sub B) and alpha precipitates were found in this zone with a lower population. Alternate immersion, anodic polarization, constant load, and slow strain tests were carried out to evaluate the general corrosion and stress-corrosion properties of autogenous and hybrid FSW prepared coupons. The experimental results will be discussed.
Document ID
Acquisition Source
Marshall Space Flight Center
Document Type
Li, Zhixian
(Lockheed Martin Michoud Space Systems New Orleans, LA United States)
Arbegast, William J.
(Lockheed Martin Michoud Space Systems New Orleans, LA United States)
Meletis, Efstathios I.
(Louisiana State Univ. Baton Rouge, LA United States)
Date Acquired
August 18, 2013
Publication Date
January 1, 1997
Subject Category
Metallic Materials
Meeting Information
Meeting: Welding Trends
Location: Pine Mountain, GA
Country: United States
Start Date: June 1, 1998
Sponsors: American Welding Society
Funding Number(s)
Distribution Limits

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