Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5456548 | Materials Science and Engineering: A | 2016 | 16 Pages |
Abstract
The hot deformation behavior of an IN718 superalloy was studied by isothermal compression tests under the deformation temperature range of 950-1100 °C and strain rate range of 0.001-1 sâ1 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 â3 character 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.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
M. Azarbarmas, M. Aghaie-Khafri, J.M. Cabrera, J. Calvo,