Alloy Three-dimensional Flow Field In A Stir Friction Welding

The study of flow field is the main aspect of fundamental study in friction stir welding. The large CFD(computational fluid dynamics) software FLUENT was used in the study to numerically simulate and analyze flow field of weld metal with finite element method during the friction stir welding course. The 3-D flow field model of 10mmLF2 aluminum alloy was built and testified by experimental data. The main contents in the study contained two parts of the measurement of actual flow field and the foundation of flow field model.Marker Fe grains were inserted into 1 Omm LF2 aluminum alloy in different positions in the study to measure actual flow field. The samples were analyzed by using EDS(energy dispersive x-ray spectroscopy) and observing the microstructure. The 3-D flow status was confirmed by observing horizontal, cross and longitudinal distributions of Fe grains in welding zone.The computational flow field was numerically simulated by using software FLUENT. Software GAMBIT was adopted to build 3-D finite element model. The limited conditions of modeling flow field were confirmed by experimental parameters. RNG k-ε turbulence model was reasonably selected to iteratively evaluate the equations. The flow model was built in this way. The simulated result accorded to the actual result by comparing with the difference of the two and modifying the limited conditions.It was very significant to study the 3-D flow field in finding out the essential of welding figuration and analyzing the hole of weld. It also was valuable to build the relationship between flow field and weld parameters and dimensions of the tool. Weld parameters could be confirmed and welding technology was optimized. Microstructure and performance were controlled. Moreover, the study of flow field established foundation for further studying the coupling of thermal flow in friction stir welding.