This study aimed at dissimilar metal butt friction stir welding in various types of processing conditions on the welding product hardness, tensile strength, etc. At first, using the AA-5052 as the similar material in FSW(friction stir welding) process. Compare the affected in different working parameter such like tool rotation speed, tool feed rate, etc. During FSW process, using the K-type thermal couple to monitoring the temperature history at different position in the specimen. According the result and finding the best working parameter. As the result shown, the high speed rotating rate or the low feeding rate will cause more heat energy in the specimen. In completed FSW condition, the range of rotating rate is 600-900rpm, the feeding rate is 40-80mm/min, the preheating temperature is suitable in 350¢J. For the aluminum alloy and copper alloy of the dissimilar metal friction stir welding, specimen¡¦s surface has holes and large chip by lacking heat during using the tool diameter of 12mm to weld, use the tool diameter of 15mm to weld can enhance the heat during the welding process and improve the production of surface.

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xi, 73 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 63-66).

Thesis (M. S. in Mechanical Engineering)--Vanderbilt University, May 2009. / Title from title screen. Includes bibliographical references.

Thesis (M. S. in Mechanical Engineering)--Vanderbilt University, May 2009. / Title from title screen. Includes bibliographical references.

Thesis (M.S.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 108-109).

Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2007. / Includes bibliographical references (p. 95-96).

Thesis (Ph.D.)--Brigham Young University. Dept. of Mechanical Engineering, 2008. / Includes bibliographical references (p. 167-172).

Thesis (M.S.)--Missouri University of Science and Technology, 2008. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 2, 2008) Includes bibliographical references.

Thesis (Ph. D.)--Missouri University of Science and Technology, 2009. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed July 16, 2010) Includes bibliographical references (p. 175-181).

This research project was conducted to increase weld gap tolerance in Friction Stir Welding (FSW) of 8 mm thick aluminum alloy 6082 – T6. Investigation was done on I-STIR PDS platform and a Johnford milling machine. The research project involved tool-pin design with varying re-entrant features and varying parameters as a method of weld gap closing to produce successful welds. Direction of spindle rotation and dwell time were established as part of a preliminary study. Clockwise spindle rotation with 20 seconds dwell time allows sufficient plasticity and improved material flow which assisted in achieving welds with prior 30 percent weld gap of the plate thickness. Final welds were made using three rotational speeds and feed rates with sufficient plunging to prevent root defects. Analysis of the results were detailed which include vickers microhardness test, tensile test and metallographic observation to access the suitability of the weld structure. From the set of tool-pins designed, the flare tool-pin gave a well-defined weld nugget with improved stirring at the weld root. Also, with a concave shoulder, right hand threaded tool-pin and counterclockwise flutes undergoing a clockwise spindle rotation, plasticized material flow was upward which was beneficial in reducing the amount of plate thinning. The right hand thread counter clockwise flute with a flute machined in the foot exhibited superior tensile strength for welds containing 30 percent weld gap.