Annealing is one of the most efficient heat treatment to refine the grain microstructure in metal alloys.Prior to the annealing,an aging treatment can be implemented to precipitate the second phases for more nucleation sites in deformed mixed grains during subsequent recrystallization.However,the underlying mechanism behind the second phases and recrystallization has not yet been fully understood.Taking a typical deformed nickel(Ni)-based(GH4169)superalloy as an exapmle,this research aims to clairfy the connections between the recrystallization and delta(δ)phase(Ni3Nb)during annealing.All deformed samples were also treated by aging and then annealing.The results show that the microstructure and component of δ phase dominated the recrystallization nucleation in the Ni-based alloy.Moreover,there was the presence of the δ phase interval limiting nucleation(PILN)and δ phase protecting nucleation(PPN),when a high content of close-set phase was precipitated from the matrix.The PILN determined the primary condition for the recrystallization nucleation that happended at the interval of 8 phase larger than the critical nucleation size.The peak nucleation occurred in the PPN,where the recrystallization nucleus were free of the penetration by the adjacent grains,before the nucleation incubation time was reached.Thus,a new feasible JN theory was proposed to determine the maximum domain of recrystal-lization nucleation under close-set precipitated phases.All the possible nucleation sites were assumed under PPN in the JN theory.As such,the original microstructure can be expected to design for the an-nealing via the aging process.A quantitative evaluation of recrystallization nucleation can also achieved in the Ni-based alloys during aging.

Guanqiang Wang;Mingsong Chen;Yongcheng Lin;Hongbin Li;Yuqiang Jiang;Yanyong Ma;Chengxu Peng;Jinliang Cai;Quan Chen

School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;State Key Laboratory of High Performance Complex Manufacturing,Changsha 410083,China;Light Alloy Research Institute,Central South University,Changsha 410083,China;College of metallurgies and energy,North China University of Science and Technology,Tangshan 063009,China

材料科学技术（英文版）

[1]Guanqiang Wang;Mingsong Chen;Yongcheng Lin;Hongbin Li;Yuqiang Jiang;Yanyong Ma;Chengxu Peng;Jinliang Cai;Quan Chen-.Recrystallization nucleation under close-set δ phase in a nickel-based superalloy during annealing)[J].材料科学技术（英文版）,2022(20):166-176

exapmle,clairfy,PILN,happended

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