AA6061半固态下非连续相的同步辐射研究

Discontinuous Phase of Semi-solid AA6061 through Synchrotron Radiation Technology

利用同步辐射X射线CT扫描技术对二次加热不同温度下AA6061试样组织进行扫描和三维重构,研究了二次加热过程中半固态初生α-Al相及其内部缺陷等非连续相的演变。结果表明,随着二次加热温度的升高,缩孔被液相补偿,缩孔出现几率下降,气孔出现几率上升,而内部缺陷整体有所减少,有利于半固态加工成形。富Fe相会阻碍液相对缩孔的补偿,不利于内部缺陷消除。

Synchrotron radiation X-ray computed tomography technology was adopted to reconstruct the three-dimensional microstructure of AA6601 billet with different reheating temperature.Three-dimensional internal defects were analyzed quantitatively to investigate influence of reheating temperature on internal defects evolution.The results reveal that with the increase of reheating temperature,the shrinkage cavity can be compensated by the liquid phase,leading to the decrease of shrinkage percentage and the rise of the gas pore as well as the decline of the internal defects ratio,which are beneficial for the semi-solid forming.However,the iron-rich phase can prevent liquid phase from compensating the shrinkage cavity,which is not conducive to eliminating the internal defects.