Directional Migration Behavior of Alloying Elements in the Rafting Process of the Single Crystal Superalloy DD6

This paper investigated the directional migration behavior of the alloying elements 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 was 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 fade away gradually in vertical direction. Statistical analysis of the alloy components by TEM reveals 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, and obviously concentrate in the crossing area of the above mentioned channels.