Precipitation, deformation and fracture behaviour of a thermomechanically processed nimonic PE 16 superalloy

Achieving High Tensile Strength of Heat-Resistant Ni-Fe-Based Alloy by Controlling Microstructure Stability for Power Plant Application

“…Thus, the rapid reduction of strength above 700 • C could be partly attributed to the onset of dynamic recovery and/or recrystallization. A similar dynamic recovery and recrystallization softening mechanism and its influence on tensile strength have been reported in other Ni-based superalloys [19,20]. The fracture behaviors of this Ni-Fe-based alloy exhibited a mixed trans-granular ductile fracture and intergranular fracture mode from room temperature to 750 • C. According to the microcracks along the grain boundaries from the lateral surface view in Figure 3b3,c3, it can be proposed that the intergranular fracture mode became dominant above 700 • C, especially at 750 • C. Dislocation interactions with the grain boundary carbides could cause stress concentration at the interfaces, further leading to micro-void formation or microcrack initiation and propagation along grain boundaries, which is consistent with the crack observed in the grain boundaries in Figure 3c2.…”

“…The fracture behaviors of this Ni-Fe-based alloy exhibited a mixed trans-granular ductile fracture and intergranular fracture mode from room temperature to 750 • C. According to the microcracks along the grain boundaries from the lateral surface view in Figure 3b3,c3, it can be proposed that the intergranular fracture mode became dominant above 700 • C, especially at 750 • C. Dislocation interactions with the grain boundary carbides could cause stress concentration at the interfaces, further leading to micro-void formation or microcrack initiation and propagation along grain boundaries, which is consistent with the crack observed in the grain boundaries in Figure 3c2. At 750 • C, dynamic recovery of deformation dislocation becomes strong, and dynamic recrystallization of γ matrix retards the microcrack growth, thereby enhancing the fracture ductility [20,21].…”

Microstructural evolution in austenitic heat-resistant cast steel 35Cr25Ni12NNbRE during long-term service

“…Some researchers reported that PFZs could form along grain boundaries in many precipitation strengthened alloys including aluminum alloys [19][20][21][22][23], superalloy [24,25] and austenitic steels [26,27]. The PFZ formed by the vacancy depletion and the solute depletion mechanisms [19][20][21][22][23][24][25].…”

“…The PFZ formed by the vacancy depletion and the solute depletion mechanisms [19][20][21][22][23][24][25]. PFZ brought to detrimental effect on the stress corrosion and mechanical properties [22].…”