γ′析出型耐熱合金の時効処理による析出過程について

γ′析出型耐熱合金の系統的研究-II

抄録

In the previous reports, the author introduced the age-hardenable characteristics and high temperature load-carrying ability of the various gamma-prime precipitated alloys varied from Ni-base alloys to Fe-base alloys
In this investigation, the author studied the precipitation process during aging of these alloys by X-ray diffraction tests and electron metallography.
By the X-ray diffraction tests on the electrolytic extracts from the various specimens after up to 1, 000h aging, MC, M7C3, M23C6, γ′, σ and β phases were identified. High-Ni alloys precipitated M7C3 besides MC, M23C6 and γ′ phase. On the other hand, high-Fe alloys precipitated the massive β phases. The matrix, γ′ lattice parameters and γ′-matrix lattice mismatch of the alloys comprizing no β phase were hardly changed in the precipitation process during 1, 000h aging. The γ′-matrix lattice mismatches were increased with the Co contents, and were decreased with the Fe contents. γ′ particle sizes were increased with aging time, but the growth of γ′ particles were retarded as the Co and Fe contents of matrix composition were enhanced. The amount of γ′ particles were increased with the aging time and the Co contents, but were decreased as the Fe content of matrix composition was raised.
It was presumed that these precipitated β phases changed as follows by aging: γ′→γ′+β→β