电脉冲固溶对Al-22％Si-1.5％Cu合金组织的影响

Effects of current pulse during solution process on microstructure of AI-22%Si-1.5%Cu alloy

利用光学显微镜观察及显微硬度测量等方法研究了在脉冲电流作用下,Al-22%Si-1.5%Cu合金经过固溶、时效后其显微组织及基体性能的变化。结果表明,采用短时间高密度脉冲电流作用于Al-22%Si-1.5%Cu合金固溶过程前期(作用时间为120S),可明显改善该合金初生硅相及Al_2Cu相的形态和分布、显著提高基体的显微硬度。在固态相变经典形核理论的基础上,本文讨论了其作用机理。分析后认为脉冲电流影响了溶质原子的非平衡扩散过程,提高了固态相变的驱动力场从而降低扩散能垒,强化了溶质粒子扩散过程。

By using the metallography and micro-hardness tester we have investigated the effects of the electric pulse treatment on the structure of Al-22%Si-1.5%Cu alloy during the solution treatment. The results show that the shape of primary silicon phase and Al2Cu phase has been refined and the micro-hardness of matrix increases from 86.65kg/mm^2 to 112.58kg/mm^2 after applying the electric pulse to the solution process. Based on the classical nucleation theory of solid-state phase changes, subsequently, we have discussed the mechanism. Then, it is analyzed that the non-equilibrium diffusion of the solute atoms in the matrix is promoted, and then the energy barrier of atom diffusion decreases under the action of electric pulse treatment.