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 precipita...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 waterquenched 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 c 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.展开更多
Effect of segregation behaviors of P at different cooling rates on the precipitation of γ" and γ' phases and the corresponding strength are investigated. The precipitation of γ" and γ' phases dur...Effect of segregation behaviors of P at different cooling rates on the precipitation of γ" and γ' phases and the corresponding strength are investigated. The precipitation of γ" and γ' phases during cooling is sensi-tive to P concentration. With increasing the concentration of Pf the amount of γ" and γ' particles increases after air cooling. With decreasing the cooling rate, the accelerating effect of P on the precipitation of γ" and γ' phases decreased first and then increased, which demonstrates the concentration of P dissolved in the grain interior decreases first and then increases. The different effects of P on γ"and γ' phases with different cooling rates were analyzed by the kinetic characteristic of nonequilibrium grain-boundary seg-regation. The characteristic of nonequilibrium grain-boundary segregation of P in superalloy is further confirmed, and the phenomenon caused by critical cooling rate is captured.展开更多
基金the financial support from the National Science and Technology Major Project of China (No. J2019-VI-0004-0117)National Natural Science Foundation of China (No. 51905301)。
文摘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 waterquenched 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 c 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.
文摘Effect of segregation behaviors of P at different cooling rates on the precipitation of γ" and γ' phases and the corresponding strength are investigated. The precipitation of γ" and γ' phases during cooling is sensi-tive to P concentration. With increasing the concentration of Pf the amount of γ" and γ' particles increases after air cooling. With decreasing the cooling rate, the accelerating effect of P on the precipitation of γ" and γ' phases decreased first and then increased, which demonstrates the concentration of P dissolved in the grain interior decreases first and then increases. The different effects of P on γ"and γ' phases with different cooling rates were analyzed by the kinetic characteristic of nonequilibrium grain-boundary seg-regation. The characteristic of nonequilibrium grain-boundary segregation of P in superalloy is further confirmed, and the phenomenon caused by critical cooling rate is captured.
