Acta Metallurgica Sinica (English Letters) ›› 2023, Vol. 36 ›› Issue (12): 2013-2030.DOI: 10.1007/s40195-023-01608-6

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Recrystallization Behavior of the New Ni-Co-Based Superalloy with Fusion Structure Produced by Electron Beam Smelting Layered Solidification Technology

Hongyang Cui1,2, Yi Tan1,2, Rusheng Bai1,2, Lidan Ning1,2, Chuanyong Cui3, Xiaogang You4, Pengting Li1,2()   

  1. 1School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
    2Key Laboratory for Energy Beam Metallurgy and Advanced Materials Preparation of Liaoning Province, Dalian 116024, China
    3Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    4Zhongyuan Critical Metals Laboratory, Zhengzhou University, Zhengzhou 450001, China
  • Received:2023-04-18 Revised:2023-08-22 Accepted:2023-08-23 Online:2023-10-30 Published:2023-10-30
  • Contact: Pengting Li

Abstract:

The new Ni-Co-based superalloy featuring a "fusion structure" was produced utilizing electron beam smelting layered solidification technology (EBSL). Experimental examination of hot compression deformation with varied settings for EBSL and conventional duplex process melting Ni-Co superalloys was performed. As per the study, EBSL-Ni-Co superalloys exhibited enhanced recrystallization susceptibility during hot deformation. Furthermore, elevating deformation temperature, lowering strain rate, and augmenting strain collectively contribute to enlarging the volume fraction of dynamically recrystallized grains. Aberrant growth of grains occurred when the deformation temperature equaled γ′ sub-solvus temperature and the strain rate was slower. Moreover, exceeding the γ′ solvus temperature during deformation significantly increases the particle size of dynamic recrystallization (DRX) grains. The γ′ phase can effectively modulate the DRX grain size through the pegging effect. Additionally, it was revealed that the presence of the fusion structure aids in the generation of continuous dynamic recrystallization, discontinuous dynamic recrystallization, and twinning-induced dynamic recrystallization while the alloy undergoes hot deformation. This mechanism promotes DRX granule formation and permits complete recrystallization. Ultimately, the fusion structure was identified as playing a catalytic role in the dynamic recrystallization process of the new Ni-Co superalloy.

Key words: Dynamic recrystallization, Hot deformation, Electron beam smelting, Ni-Co-based superalloy, Fusion structure