The NTIS website and supporting ordering systems are undergoing a major upgrade from 8PM on September 25th through approximately October 6. During that time, much of the functionality, including subscription and product ordering, shipping, etc., will not be available. You may call NTIS at 1-800-553-6847 or (703) 605-6000 to place an order but you should expect delayed shipment. Please do NOT include credit card numbers in any email you might send NTIS.
Documents in the NTIS Technical Reports collection are the results of federally funded research. They are directly submitted to or collected by NTIS from Federal agencies for permanent accessibility to industry, academia and the public.  Before purchasing from NTIS, you may want to check for free access from (1) the issuing organization's website; (2) the U.S. Government Printing Office's Federal Digital System website; (3) the federal government Internet portal; or (4) a web search conducted using a commercial search engine such as
Accession Number ADA562397
Title Spatial Mechanical Response and Strain Gradient Evolution of Friction Stir Welded Aluminum-2139.
Publication Date Feb 2012
Media Count 30p
Personal Author B. Justusson C. Fountzoulas C. Yen J. Medintz J. Yu
Abstract With current involvements of the U.S. Military in various peace- keeping and combat operations throughout the world, there is an increase in the deployment of armored military vehicles. Traditional armoring techniques have performed well against particular threats, but, in the recent combat operations, a new threat of improvised explosive devices, the vulnerability of the undercarriage, is being exposed. While thick, steel-structural members have been used in the past, an effort to make them more agile and deployable has caused a push toward lightweight materials. Advanced aluminum alloys, such as AA-2139, are attractive candidates because of their high strength and lower density than steel. Single-body construction can eliminate joint failure but requires a new joining technique. Friction stir welding (FSW) is a solid-state joining technique that combines extreme plastic deformation coupled with localized heat flux to create unique microstructure joints. In general, the mechanical properties are dependent on the formation of the microstructure. To the best of our knowledge, these microstructural zones and the quality of the weld have not fully been characterized under blast loading. Finite-element simulations have been used to predict the mechanical response of blast loading, but the effects of the microstructural zones on blast loading are not fully understood. In the present work, the spatial mechanical response of a FSW joint is analyzed to determine the spatial mechanical properties.
Keywords Aluminum alloys
Finite element method
Friction stir welding (FSW)
Friction welding
Heat flux
Mechanical properties
Solid state

Source Agency Non Paid ADAS
NTIS Subject Category 71N - Nonferrous Metals & Alloys
Corporate Author Oak Ridge Inst. for Science and Education, TN.
Document Type Technical report
Title Note Final rept. Jul 2007-Aug 2011.
NTIS Issue Number 1225
Contract Number ORISE 1120-1120-99

Science and Technology Highlights

See a sampling of the latest scientific, technical and engineering information from NTIS in the NTIS Technical Reports Newsletter

Acrobat Reader Mobile    Acrobat Reader