DD6单晶合金筏化过程中元素定向迁移行为

Directional migration behavior of alloying element in the rafting process of the single crystal superalloy DD6

摘要:

对[001]取向DD6单晶合金进行1000°C、300MPa条件下的拉伸蠕变实验,以研究合金的筏化现象以及元素的定向迁移行为,SEM对合金显微组织的观察表明,γ′相在温度和应力的作用下发生了筏化,且筏化方向与应力轴垂直,同时平行于应力轴的基体通道变宽,垂直方向的基体通道逐渐消失。TEM对合金的成分统计分析表明,合金中Al、Re、W元素发生了定向迁移,其中Al向与应力轴平行的基体通道扩散,而Re、W向与应力轴垂直的基体通道扩散,并主要富集于相互垂直的基体通道的交叉区域。

Abstract:

This paper investigates the directional migration behavior of the element in the rafting process of the single crystal superalloy DD6 with [001] orientation under 300 MPa at 1000 °C. The microstructure of the single crystal superalloy DD6 is acquired by SEM. The results indicate that the rafting direction of γ′ phase is nearly perpendicular to stress axis. The matrix channel running parallel to the stress axis gets wider, but it will tend to fade away in vertical. Statistical analysis of the alloy components by TEM shows the directional migrations of the elements Al, Re and W in the single crystal superalloy DD6. The element Al spreads to the matrix channel which is parallel to the stress axis, while Re and W diffuse to the matrix channel which is perpendicular to the stress axis.