Enhanced creep resistance induced by synergistic effects between Fe and P in Ni-based model alloy

The segregation behavior of phosphorus (P) and its effects on microstructures and creep properties (650 °C/120 MPa) of NiCr (0Fe) and NiCrFe (15Fe) model alloys were systematically investigated. The alloy with combined additions of Fe and P demonstrates superior creep resistance, which results from the precipitation of nano-sized γ′ phase. This phenomenon is attributed to the synergistic effect of Fe and P, which facilitates the redistribution of P atoms from grain boundaries into the γ′ phase. The primary deformation mechanism involves dislocations shearing of γ′ phase. Conversely, individual addition of P in 0Fe alloy results in a slight deterioration of creep rupture life, where only dislocation slip predominates as the deformation mechanism. This work contributes valuable insights into the interaction between Fe and P concerning creep properties and offers guidance for future microalloying designs.