Dynamic recrystallization behavior of a novel duplex Ni-W-Co-Mo medium-heavy alloy

The hot deformation behavior of a novel duplex Ni-42W-10Co-10Mo (wt.%) medium-heavy alloy (MHA) was studied using Gleeble-3800 within temperature ranging from 1150 °C to 1300 °C under strain rates of 0.001–1 s⁻¹. The as-cast alloy exhibited a hypoeutectic microstructure, characterized by a face-centered cubic matrix and μ phase distributed in the inter-dendritic regions. The hot deformation activation energy was determined to be 855.6 kJ/mol, primarily due to the precipitation of secondary μ phases during deformation. The μ phase alloys showed a positive effect on dynamic recrystallization (DRX), Particle-stimulated nucleation (PSN) provided numerous nucleation sites for DRX, while the pinning effect of the μ phase inhibited grain growth, leading to formation of a fine-grained microstructure. Furthermore, a strain-induced boundary migration (SIBM) nucleation mechanism was observed in the alloy. The combined effects of PSN and SIBM facilitated formation of refined dynamic recrystallized grains. The hot deformation window of Ni-42W-10Co-10Mo MHA was determined as deformation temperature of 1200 °C under strain rates of 0.01–0.1 s⁻¹ based on hot processing map and microstructural evolution.