LY12铝合金摩擦焊接过程的电场效应

定量研究了外加强电场对LY12铝合金摩擦焊接头热影响区（HFZ）中动态再结晶区宽度与晶粒尺寸的影响，并初步探讨了其影响机制。实验结果表明，外加强电场使动态再结晶区晶粒细化、等轴性提高，超细等轴晶区亦加宽。此外，采用较高焊接压力时，电场的引入使焊接接头的动态再结晶区宽度增大10％－30％；采用中等摩擦压力施焊时，电场的作用不但使焊接接头动态再结晶区宽度明显增加，而且还影响其沿径向的分布形态，使近轴心线处的动态再结晶区宽度趋于均匀，可以推断，外加强电场可使摩擦焊接头更易发生动态再结晶，而且强电场使焊合区组织的细化与均匀化，有利于提高焊接接头性能。

EXTERNAL ELECTRIC FIELD EFFECT ON MICROSTRUCTURE OF FRICTION WELDED JOINT OF DURALUMIN LY12

The width and the grain size in dynamic recrystallization zone (DRZ) of friction welded joint of duralumin LY12 under an external electric field have been studied quantitatively, and the mechanism of the electric field effect has also been discussed. The results show that the external electric field effect distinctly leads to decrease the microstructure distribution gradient along the axial direction and grain size, advance the equiaxial characteristics of grain and widen the equiaxial grain zone. In addition, the electric field effect results in increasing of the width of the DRZ from 10% to 30% under higher friction pressure. Under the middle friction pressure, the electric field effect not only results in obviously increasing the width of DRZ, but also changing the radial distribution rules of DRZ. The uniformity of microstructure and deformation, and refined grain of welded zone, resulting from the electric field effect, are favorable to the improvement of mechanical property of welded joints.