Growth twins of R phase in the high Mo-containing nickel-base single crystal superalloy

The topological close packing phases in nickel-base single crystal superalloy aged at 1100 °C for 1000 h was investigated by the spherical aberration-corrected transmission electron microscope. There are R phases precipitated in the matrix, with the hexagonal lattice parameter as a = b = 11.154 Å, c = 17.782 Å. There are lamellar contrasts at the tip of the R phase, which were recognized to be {1-10-1} 〈01-1-1〉 type growth twins. The HRTEM results confirm that the formation of growth twins in R phase can release misfit stress to coordinate the distorted relationship between the R phase and the matrix. (paper)