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Abstract: A
three-dimensional friction stir welding(FSW) process model is developed
based on fluid mechanics. The material transport in the welding process
is regarded as a laminar, viscous and non-Newtonian liquid flows past a
rotating pin. A criterion to divide the weld zone is given on the basis
of cooperation of velocity field and viscosity field. That is, the
h0-easy-flow-zone existed near the tool pin is corresponded to the weld
nugget zone, the area between theh0-easy-flow-zone andh1-viscosity-band
is corresponding to TMAZ. Results of the simulation show that the
material in the middle part of the weld flows vertically. In the
retreating side the material is pushed up and in the advancing side the
material is pushed down. Material flow visualization experiments of
marker insert technology are used to validate the simulated results. The
experimental images can agree well with the simulated results. Under
higher welding speeds, material separated motion can be seen in the
shoulder-pin transition part, and an actual welding defect of void is
observed at the same position in the weld seam.
Key words: Friction
stir welding Flow Numerical simulation Al 2014 alloy
CLC No: TG453
国家863计划资助项目(2002AA331160).
Received 20050727, received in revised form 20060204
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