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Delta precipitation in wrought Inconel 718 alloy; the role of dynamic recrystallization

Journal Article


Abstract


  • In DELTA processing of Inconel 718 alloy, �� phase plays a vital role in final grain refinement, whose precipitation during intermediate thermal cycles is tailored by prior wrought structure. Therefore, it is necessary to renew insights into the effect of wrought structure on the morphology and quantity of �� phase. From this point, this work was conducted to investigate the �� precipitation behaviors in wrought Inconel 718 alloy. The results show that the �� precipitation behaviors are tailored by prior dynamic recrystallization (DRX) degree. Under partial DRX, �� precipitation exhibits twofold characteristics of preferential GB-precipitation accompanied by sluggish intragranular precipitation; while modified into predominant homogeneous GB-precipitation by fully DRX, in spite of the presence of few intragranular �� precipitates. After hot deformation, the equilibrium �� content is improved and inversely proportional to DRX degree. After 24 h aging at 900 ��C, the volume fraction of �� phase is 38.6% and 27.9% for partial and fully DRX, respectively, compared to 15.1% for strain-free state. The GB-�� nucleation process is accelerated due to the occurrence of DRX, and firstly finished in few minutes; differently, the intragranular �� nucleation is grain-dependent, that promoted within unrecrystallized grains but inhibited within DRX grains. The ���encounter��� phenomena are observed during �� growth, and some particular coalescence mechanisms are proposed.

Publication Date


  • 2017

Citation


  • Zhang, H., Li, C., Guo, Q., Ma, Z., Huang, Y., Li, H., & Liu, Y. (2017). Delta precipitation in wrought Inconel 718 alloy; the role of dynamic recrystallization. Materials Characterization, 133, 138-145. doi:10.1016/j.matchar.2017.09.032

Scopus Eid


  • 2-s2.0-85030309017

Start Page


  • 138

End Page


  • 145

Volume


  • 133

Issue


Place Of Publication


Abstract


  • In DELTA processing of Inconel 718 alloy, �� phase plays a vital role in final grain refinement, whose precipitation during intermediate thermal cycles is tailored by prior wrought structure. Therefore, it is necessary to renew insights into the effect of wrought structure on the morphology and quantity of �� phase. From this point, this work was conducted to investigate the �� precipitation behaviors in wrought Inconel 718 alloy. The results show that the �� precipitation behaviors are tailored by prior dynamic recrystallization (DRX) degree. Under partial DRX, �� precipitation exhibits twofold characteristics of preferential GB-precipitation accompanied by sluggish intragranular precipitation; while modified into predominant homogeneous GB-precipitation by fully DRX, in spite of the presence of few intragranular �� precipitates. After hot deformation, the equilibrium �� content is improved and inversely proportional to DRX degree. After 24 h aging at 900 ��C, the volume fraction of �� phase is 38.6% and 27.9% for partial and fully DRX, respectively, compared to 15.1% for strain-free state. The GB-�� nucleation process is accelerated due to the occurrence of DRX, and firstly finished in few minutes; differently, the intragranular �� nucleation is grain-dependent, that promoted within unrecrystallized grains but inhibited within DRX grains. The ���encounter��� phenomena are observed during �� growth, and some particular coalescence mechanisms are proposed.

Publication Date


  • 2017

Citation


  • Zhang, H., Li, C., Guo, Q., Ma, Z., Huang, Y., Li, H., & Liu, Y. (2017). Delta precipitation in wrought Inconel 718 alloy; the role of dynamic recrystallization. Materials Characterization, 133, 138-145. doi:10.1016/j.matchar.2017.09.032

Scopus Eid


  • 2-s2.0-85030309017

Start Page


  • 138

End Page


  • 145

Volume


  • 133

Issue


Place Of Publication