2005 Volume 46 Issue 10 Pages 2268-2275
In this study, the effect of Mg content on friction stirred Al–Mg alloy is discussed, and the experimental results indicate that grains of parent plate which are refined through FSP (friction stir processing) are effective in enhancing tensile properties of materials through FSP and improving the vibration fracture resistance of friction stirred specimens. It should be noted that the deterioration of vibration fracture resistance can be recognized as Mg content increases, the grain size actually has been refined by FSP. From crack propagation result, an intergranular crack propagation feature can be recognized in the specimen with higher Mg content, and it is reasonable to suggest that the precipitation of β phase plays an important role in the deterioration of vibration fracture resistance. However, all cross-sectioned microstructures at stir zone show that distinct finer grains which can be acquired by dynamic recrystallization during FSP. That meaningful improvement of uniform elongation on friction stirred specimens can be recognized is not only resulted from controlling the grain size factor, but also microstructural characteristics factor which are resulted from high temperature shear deformation.