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Full-Text Articles in Engineering

Effects Of Processing Parameters On The Embrittlement Of Self Reacting Friction Stir Welds, David Eric Taylor Jan 2009

Effects Of Processing Parameters On The Embrittlement Of Self Reacting Friction Stir Welds, David Eric Taylor

LSU Master's Theses

Friction Stir Welding (FSW) has been adopted as one of the major welding processes for joining Aluminum. Many aerospace and marine structures are welded through this novel FSW processes currently. The Lockheed Martin Space Systems (LMSS), Michoud Operations, in New Orleans is continuously pursuing Friction Stir Welding technologies in its efforts to advance fabrication of the external tanks of the space shuttle. Recently, a reduction in mechanical strength (embrittlement) has been observed especially in self-reacting (SR) friction stir welds. This strength reduction was attributed to Residual Oxide Defects (ROD) but the exact reasons for this type of behavior needed to …


Effect Of Finite Geometry On Solidification Microstructure In Beam-Based Fabrication Of Thin Wall Structures, Satish C. Kuchi Jan 2009

Effect Of Finite Geometry On Solidification Microstructure In Beam-Based Fabrication Of Thin Wall Structures, Satish C. Kuchi

Browse all Theses and Dissertations

With the advent of Rapid Protyping (RP) in the manufacturing industry, many newtechnologies came into development for quick fabrication of materials. One of the most versatile fabrication process among them is additive manufacturing. Laser based manufacturing (LBM) and electron beam manufacturing (EBM) processes use the energy from a laser or electron beam to build up structures layer by layer directly from powdered metals and wire feed stock. It has been determined from previous work that solidification cooling rate and thermal gradients are the important factors for controlling microstructure (grain size and morphology) and resulting mechanical properties of the deposit. The …