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چکیده
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The influence of primary γ' precipitates on dislocation evolution in nickel-based powder metallurgy (P/M) superalloys during hot deformation is a vital issue. A significant gap remains in comprehensively understanding the influence of primary γ' precipitate on dislocation evolution for P/M superalloys. In this study, the hot deformation and microstructure evolution of a hot extruded FGH4113A alloy are investigated at varying temperatures (1050–1110 °C) and strain rates (10−1∼10−3 s⁻¹) with a low strain (0.22). The interaction mechanism between primary γ' precipitate and dislocation is discussed. During the preceding hot extrusion, dynamic recrystallization (DRX) occurs, leading to the loss of coherence between primary γ' precipitate and γ matrix. Dislocations accumulate as they cannot traverse the incoherent γ/γ' interfaces. It is found that the accumulated dislocations can re-establish coherence at partially incoherent γ/γ' interfaces during hot deformation. While dislocations penetrate the primary γ' precipitates via these coherent interfaces, they are trapped because other regions of the γ/γ' interfaces remain incoherent. This mechanism is referred to as the “incoherent primary γ' precipitate trap” (IPT-γ'p). However, at large strains, elevated temperatures, or low strain rates, dislocations are primarily consumed through DRX. Therefore, the IPT-γ'p mechanism predominantly influences dislocation motion at low strains, low temperatures, and high strain rates.
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