The coarsening behaviors of γ′ and γ″ phases in GH4169 alloy aged at 1023 and 1073 K with electric field treatment （EFT） were investigated by transmission electron microscopy （TEM） and positron annihilation li...The coarsening behaviors of γ′ and γ″ phases in GH4169 alloy aged at 1023 and 1073 K with electric field treatment （EFT） were investigated by transmission electron microscopy （TEM） and positron annihilation lifetime spectroscopy （PALS）. It is demonstrated that precipitation coarsening occurs, and the growth activation energies of γ′ and γ″phases can be decreased to 115.6 and 198.1 kJ.mo1-1, respectively, by applying the electric field. The formation of a large number of vacancies in the matrix is induced by EFT. Due to the occurrence of vacancy migration, the diffusion coefficients of A1 and Nb atoms are increased to be 1.6-5.0 times larger than those without EFT at 1023 or 1073 K. Furthermore, the formation of vacancy clusters is promoted by EFT, and the increase in strain energy for the coarsening of γ′ and γ″ phases can be counterbalanced by the formation of vacancy clusters.展开更多
Electric field treatment （EFT） was applied on GH4169 alloy during aging at 500-800℃ to investigate the microstructure and property variation of the alloy under the action of EFT. The results demonstrate that the sh...Electric field treatment （EFT） was applied on GH4169 alloy during aging at 500-800℃ to investigate the microstructure and property variation of the alloy under the action of EFT. The results demonstrate that the shortdistance diffusion of Al, Ti, and Nb atoms can be accelerated by EFT, which results in the coarsening of γ′and γ＂ phases. Meanwhile, lattice distortion can be caused by the segregation of Fe and Cr atoms, owing to the vacancy flows migrating toward the charged surfaces of the alloy. Therefore, the alloy is hardened by the application of EFT, even if the strength of the alloy is partly reduced, which is caused by precipitation coarsening.展开更多
基金financially fnancially supported by the National Natural Science Foundation of China(No.51171039)the Major State Basic Research Development Program of China(No.2010CB631203)+1 种基金the Fundamental Research Funds for the Central Universities of China(No.N100602002)the 2010 Academy Awards Sponsorship of Doctoral Candidate for Newcomer of China(No.22002096)
文摘The coarsening behaviors of γ′ and γ″ phases in GH4169 alloy aged at 1023 and 1073 K with electric field treatment （EFT） were investigated by transmission electron microscopy （TEM） and positron annihilation lifetime spectroscopy （PALS）. It is demonstrated that precipitation coarsening occurs, and the growth activation energies of γ′ and γ″phases can be decreased to 115.6 and 198.1 kJ.mo1-1, respectively, by applying the electric field. The formation of a large number of vacancies in the matrix is induced by EFT. Due to the occurrence of vacancy migration, the diffusion coefficients of A1 and Nb atoms are increased to be 1.6-5.0 times larger than those without EFT at 1023 or 1073 K. Furthermore, the formation of vacancy clusters is promoted by EFT, and the increase in strain energy for the coarsening of γ′ and γ″ phases can be counterbalanced by the formation of vacancy clusters.
基金financially supported by the National Natural Science Foundation of China (No.51171039)the Major State Basic Research Development Program of China (No.2010CB631203)
文摘Electric field treatment （EFT） was applied on GH4169 alloy during aging at 500-800℃ to investigate the microstructure and property variation of the alloy under the action of EFT. The results demonstrate that the shortdistance diffusion of Al, Ti, and Nb atoms can be accelerated by EFT, which results in the coarsening of γ′and γ＂ phases. Meanwhile, lattice distortion can be caused by the segregation of Fe and Cr atoms, owing to the vacancy flows migrating toward the charged surfaces of the alloy. Therefore, the alloy is hardened by the application of EFT, even if the strength of the alloy is partly reduced, which is caused by precipitation coarsening.
