Effect of rhenium and ruthenium on the deformation and fracture mechanism in nickel-based model single crystal superalloys during the in-situ tensile at room temperature

In-situ tensile experiments of Ni-Al, Ni-Al-Re and Ni-Al-Re-Ru model single-crystal superalloys were performed in scanning electron microscope (SEM) at room temperature. The plastic deformation mechanisms of all the three model superalloys were double-oriented slipping of dislocations. Micro-cracks were often formed at the intersection of two sets of slip lines. The fracture surfaces of Ni-Al and Ni-Al-Re-Ru alloys were nearly parallel to (010) planes and that of the Ni-Al-Re alloys was nearly parallel to (1−11) plane. The dislocation configuration was analyzed by transmission electron microscopy (TEM). The a/2 dislocation pairs coupled with antiphase boundary (APB) cut into γʹ phase in the Ni-Al and Ni-Al-Re-Ru model superalloys. In addition to these dislocations, stacking faults also cut into γʹ phase in Ni-Al-Re model superalloys. The different fracture surfaces of different model single-crystal superalloys were attributed to the influence of elements Re and Ru on the dislocation configuration.