Numerical simulation of 2014 aluminum alloy friction stir welding process

A three-dimensional friction stir welding (FSW) process model for 2014 aluminum alloy is developed based on fluid mechanics. The material transport in the welding process is regardedas laminar, viscous and non-Newtonian liquid flowpassing a rotating pin. A criterion to divide the weld zone is given on the basis of cooperation of velocity field and viscosity field. Thatis, the eta(0)-easy-flow-zone existed near the tool pin is corresponded to the weldnugget zone, the area between the eta(0)-easy-flow-zone and eta(1)-viscosity-band is corresponded to TMAZ. Results of the simulation show that the material in the middle part of the weldflows 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-