Dynamic recrystallization mechanisms and twining evolution during hot deformation of Inconel 718

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:678

Article

Azarbarmas, M.¹  Aghaie-Khafri, M.¹  Cabrera, J. M.²  Calvo, J.² 

[1] KN Toosi Univ Technol, Fac Mat Sci & Engn, Tehran 1999143344, Iran

[2] Univ Politecn Cataluna, ETSEIB, Dept Ciencia Mat & Engn Met, Av Diagonal 647, E-08028 Barcelona, Spain

关键词: Inconel 718;    Hot compression test;    EBSD;    Misorientation;    Twinning;   

DOI  :  10.1016/j.msea.2016.09.100

来源: Elsevier

【 摘 要 】

The hot deformation behavior of an IN718 superalloy was studied by isothermal compression tests under the deformation temperature range of 950-1100 degrees C and strain rate range of 0.001-1 s(-1) up to true strains of 0.05, 0.2, 0.4 and 0.7. Electron backscattered diffraction (EBSD) technique was employed to investigate systematically the effects of strain, strain rate and deformation temperature on the subgrain structures, local and cumulative misorientations and twinning phenomena. The results showed that the occurrence of dynamic recrystallization (DRX) is promoted by increasing strain and deformation temperature and decreasing strain rate. The microstructural changes showed that discontinuous dynamic recrystallization (DDRX), characterized by grain boundary bulging, is the dominant nucleation mechanism in the early stages of deformation in which DRX nucleation occurs by twining behind the bulged areas. Twin boundaries of nuclei lost their Sigma 3character with further deformation. However, many simple and multiple twins can be also regenerated during the growth of grains. The results showed that continuous dynamic recrystallization (CDRX) is promoted at higher strains and large strain rates, and lower temperatures, indicating that under certain conditions both DDRX and CDRX can occur simultaneously during the hot deformation of IN718.

【 授权许可】

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