Effects of Stress‐Aging Pretreatment on Hot Deformation Behavior and Microstructure Evolution of a Ni–Cr–Nb–Mo–Ti Alloy

Abstract

Hot deformation behavior and microstructure evolution of stress and stress‐free aged NiCrNbMoTi alloy are investigated by hot compressive tests. The impacts of stress aging upon the flow softening and dynamic recrystallization (DRX) behavior are analyzed. Also, the variations of dislocation substructures are studied. The basket‐weave δ‐phases induced by stress‐aging pretreatment can refine grains during hot deformation. On the one hand, the basket‐weave δ‐phases mutually intersect and form some enclosure spaces. Then, the dislocations which are restrained in these enclosure spaces can increase the potential sites for DRX nucleation. On the other hand, the growth of DRX grain is significantly hindered by the basket‐weave δ‐phases. The peak stress increases substantially as the stress‐aging stress rises. The dislocations pinned near the basket‐weave δ‐phases can hinder the migration of grain boundaries and accelerate the DRX process during hot deformation.

Modeling the Rheological Behavior of a Novel Hot Isostatic Pressed Powder Metallurgy Superalloy

“…[6][7][8][9] In last few years, the microstructure evolution and thermal deformation features of nickel-based superalloys had been investigated by many researchers. [10][11][12][13][14] Additionally, many studies found that the deformation parameters significantly affect the rheological behavior and grain characteristics of nickel-based superalloys. [15,16] So, it is necessary to optimize the thermal deformation processing by systematically studying the deformation mechanisms under various processing conditions and establishing the precise model to forecast the rheological behavior of P/M superalloys.…”

Comparison Study of Hot Deformation Behavior and Microstructure Evolution of Rack Steels with and without Segregation

“…Therefore, considering the strong relationship between deformation mechanism and deformation conditions, it is significantly vital to understand the hot deformation behavior of segregated and nonsegregated zones for the rack steels to optimize the hot workability and rolling process. Numerous studies of the hot deformation behavior have been conducted based on flow curves and constitutive relationships in magnesium alloys, [10][11][12] stainless steels, [13][14][15] microalloyed steels, [16][17][18] and so on. However, the effect of segregation on the hot deformation behavior is rarely reported for ultraheavy steel plates.…”