Effect of processing parameters on hot compressive deformation behavior of a new Ni–Cr–Co based P/M superalloy

Competition between work-hardening effect and dynamic-softening behavior for processing as-cast GH4720Li superalloys with original dendrite microstructure during moderate-speed hot compression

“…It is found that the flow stress curve is composed of three stages, viz. workhardening stage, softening stage and steady stage [23][24][25]. In work hardening stage, the dislocation continually increases and rapidly accumulates, resulting in an obvious work-hardening.…”

Compressive Deformation Behavior of Thick Micro-Alloyed HSLA Steel Plates at Elevated Temperatures

“…The slow strain rate and high temperature provide a longer time for the energy to accumulate and a higher mobility for nucleation. Dynamically recrystallized grain growth and dislocation annihilation are facilitated, which lead to a reduction in the flow stress [6]. Fig.…”

“…Further deformation at a strain of 0.6 led to an increase in the flow stress, which was due to the densification of the specimen during the compression test. In general, the plateau becomes larger at higher temperatures, and the initial strain hardening is associated with an increase in the dislocation density from the plastic deformation, and the formation of poorly developed sub-grain boundaries as a result of work hardening and dynamic recovery [6]. The stress achieves a steady state when a new balance between softening and hardening is obtained in the plateau [7,8].…”

Constitutive Model Based on Dynamic Recrystallization Behavior during Thermal Deformation of a Nickel-Based Superalloy

“…In the steady stage, the flow stress is maintained at a relatively stable level due to the dynamic balance between the softening and the work-hardening effects. It can be found that the true stress-strain curve can be divided into three stages: work hardening stage, softening stage, and steady stage [22,28]. In the work hardening stage, the strain is lower, and the external stress contributes to internal defects such as dislocations, which constantly increase and rapidly accumulate with the diffusion of various alloying elements.…”

“…Taking the natural logarithm of both sides of Equation (26) leads to: lnrsinhpασ s qs " lnn 3`n4 lnZ (27) lnrsinhpασ ss qs " lnn 5`n6 lnZ (28) Eventually, the values of the material constants are obtained from the plots of lnrsinhpασ s qs-lnZ and lnrsinhpασ ss qs-lnZ (Figure 15a,b). …”