Deformation and fracture measurements and mechanisms of alloy 718 at high temperature
- Univ. of South Carolina, Columbia, SC (United States)
The broad objective of this research is to improve our understanding of the crack growth process in metallic materials at elevated temperatures and aggressive environments. The need for accurate measurement of strains and displacements under these conditions led to the development the computer vision technique called High Temperature Digital Image Correlation (HTDIC). The HTDIC technique has been used to accurately measure deformations due to thermal expansion and simple tension at temperatures up to 650{degrees}C. These results of these tests are reviewed to discern the capabilities and limitations of the experimental technique. This work applies HTDIC to measure near-crack-tip deformation fields during creep crack growth of the nickel-based superalloy 718. The measured deformations are used to estimate important continuum creep crack growth parameters, such as K, J, C{sup *}, C(t) or near-tip strains. Results indicate that the crack tip strains are dominated by linear elastic conditions prior to and during crack growth. Prior to crack growth there is also a clear creep component. In addition, pre- and post-test metallographic evaluations of creep damage and other microstructural changes are conducted. The results of the full-field near-tip measurements, metallurgical evaluations and theoretical solutions are combined to develop a {open_quotes}fundamental{close_quotes} understanding of the creep crack growth process in metallic materials.
- OSTI ID:
- 175202
- Report Number(s):
- CONF-950686-; TRN: 95:006111-0123
- Resource Relation:
- Conference: Joint applied mechanics and materials summer meeting, Los Angeles, CA (United States), 28-30 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of AMD - MD `95: Summer conference; PB: 520 p.
- Country of Publication:
- United States
- Language:
- English
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