Room temperature creep behavior of a single crystal nickel-based alloys

Abstract The deformation characteristics of a single crystal nickel-based alloy containing Re during the creep at room temperature were studied by means of the creep property test, microstructure observation and the contrast analysis of dislocation configuration. The results show that during the deformation of the alloy at room temperature, the original cubic γ′ phase transforms into a rhombous shape along the direction of maximum shearing stress, and its deformation feature is that the dislocation slips in the matrix and shear the γ′ phase. The <110> superdislocation shear into the γ′ phase can cross slip from the {111} plane to the {100} plane, forming K-W lock, and can also be decomposed at the {111} plane. The dislocation configurations of (1/2)<110> partial dislocation plus antiphase boundary (APB) and (1/3)<112> partial dislocation plus SISF can effectively inhibit the slip and cross-slip of the dislocation and improve the deformation resistance of the alloy. At the later stage of creep, under the action of shear stress, the initial slip system is activated first to distort the two phases of γ/γ′, and then the secondary slip system is activated and shear the primary slip system, resulting in a large stress concentration at the delivery point and the initiation of cracks in this area. With the alternating activation of the primary slip system and secondary slip system during creep, the initiation and expansion of cracks continue. It is the damage and fracture mechanism of alloy during room temperature creep.