Continuous texture evolution during staged solid solution of Al-Cu-Mg and the influence on fatigue resistance

摘要

Continuous texture evolution of the Al-Cu-Mg alloy during the staged solid solution and corresponding influence on fatigue property has been studied by means of X-ray diffraction, electron back scattered diffraction and scanning electron microscopy. The characteristic texture transition rate X_(CGB) and orientation streamline approach was introduced to further investigate the behind mechanisms. The results show that the two-step solid solution could significantly enhance the X_(CGB), thereby contributes to reduce the fatigue crack growth rate of Al-Cu-Mg T3 sheet during stage Π The near Cube texture with high Schmid factor (SF) and low Taylor factor (TF) tends to induce significant crack deflection, crack closure and strengthened planar slip. The potential 60° twin relation and mutual transformation existed between Goss and P texture would further reduce the fine random orientation grain and inter-granular fatigue crack extension. Such above effects would be responsible for the excellent correspondence between X_(CGB) and fatigue resistance.