Effect of dynamic strain aging and precipitation on the hot deformation behavior of 253MA heat-resistant alloy

In this research, we performed an experimental investigation into the influence of dynamic strain aging (DSA) and precipitation behavior on the plastic deformation and microstructure evolution in alloy 253MA considering its service temperature. The serrated flow behavior, stress anomaly behavior and negative strain rate sensitivity are considered as the manifestation of DSA within a certain temperature range (T-DSA), which can be classified as low (550-700 degrees C), intermediate (600-750 degrees C) and high temperatures (700-790 degrees C) at 0.001s(-1), 0.01s(-1) and 0.1s(-1), respectively. The activation energy of DSA was determined to be 242kJ/mol, indicating that the diffusion of substitutional solutes, such as Cr and Ni, is mainly responsible for the DSA phenomenon. The characteristic of dislocation substructures is prone to change from linear structure to cellularization structure with a rising deformation temperature in the DSA regime. The stress anomaly behavior can be attributed to the rapid dissolution of sigma phase. The initiation of dynamic recrystallization should contribute to the disappearance of DSA by suppressing the dynamical solute atom-dislocation interaction.