A TEM Study of Creep Deformation Mechanisms in Allvac 718Plus
- ORNL
- Metals Technology, Inc
- Ohio State University
A preliminary study on the evolution of creep deformation substructure in Ni-base superalloy Allvac 718Plus has been performed. Specimens crept at 620 MPa and at temperatures ranging from 690-732 C were examined utilizing diffraction contrast TEM characterization techniques. Creep was interrupted at 1-2.5% strain in order to study the deformation substructure following a limited amount of deformation. The dominant deformation modes at each of the test temperatures were highly planar in nature and involved shearing of the matrix and precipitates on {111} glide planes. In addition, paired a/2<110> dislocations were evident which suggest an antiphase boundary shearing mechanism. Creep induced microtwinning was also observed at the highest creep temperature which was created by identical a/6<112> Shockley partial dislocations that shear the matrix and precipitates on consecutive close packed {111} glide planes.
- Research Organization:
- Oak Ridge National Laboratory (ORNL); Shared Research Equipment Collaborative Research Center
- Sponsoring Organization:
- ORNL LDRD Director's R&D
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 989713
- Country of Publication:
- United States
- Language:
- English
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