Interaction between Re and W on the microstructural stability of Ni-based single-crystal superalloys

The influences of Re and W as well as their interaction on γ′ and topologically close-packed (TCP) phases have been investigated in seven kinds of Ni-based single-crystal superalloys. The results show that after full heat treatment, the γ′ size is reduced with increasing Re, but does not change with increasing W. After thermal exposure at 1000°C for 1000?h, the TCP phase is dramatically increased with increasing Re, but increased slightly with increasing W. The TCP phase volume fraction in higher Re alloys is much more than that in lower Re alloys which have the same total content of Re and W. This indicates that W instead of Re could effectively improve the microstructural stability of Ni-based single-crystal superalloys.