Re-recognition of the Effects of Phosphorus and Boron on the γ″ and γ′ Phases in IN718 Alloy
The effects of P and B on the matrix strength and precipitations of γ ′ and γ ″ phases in the grain interior were re-recognized in this study. The combination addition of P and B markedly accelerated the precipitations of γ ′ and γ ″ phases and strengthened the matrix of IN718 alloy when air-cooled...
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Veröffentlicht in: | Acta metallurgica sinica : English letters 2019-03, Vol.32 (3), p.372-380 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The effects of P and B on the matrix strength and precipitations of
γ
′ and
γ
″ phases in the grain interior were re-recognized in this study. The combination addition of P and B markedly accelerated the precipitations of
γ
′ and
γ
″ phases and strengthened the matrix of IN718 alloy when air-cooled from high temperature, while made no difference when water-quenched from high temperature. The effect of single addition of P on the precipitations of
γ
″ and
γ
′ phases was the same with that of the combination addition of P and B, while the single addition of B had no effect on the precipitations of the two phases. Therefore, it was P rather than B which accelerated the precipitations of
γ
′ and
γ
″ phases. P could take part in the precipitations of
γ
′ and
γ
″ phases, which was revealed by electrochemical extraction and quantitative analysis of chemical composition. It also revealed that P atoms were dissolved in the
γ
matrix to a relatively high degree at the temperature that
γ
′ and
γ
″ phases began to precipitate, and consequently the precipitations of
γ
′ and
γ
″ phases were accelerated. The first-principle calculation indicated that P decreased the formation enthalpies of
γ
′ and
γ
″ phases when it occupied the Ni lattice sites in the two phases, which explained the effect of P on the
γ
′ and
γ
″ phases. |
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ISSN: | 1006-7191 2194-1289 |
DOI: | 10.1007/s40195-018-0786-5 |