High-temperature measurements of lattice parameters and internal stresses of a creep-deformed monocrystalline nickel-base superalloy

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02649768· OSTI ID:250727

Biermann, H; Strehler, M; Mughrabi, H ^[1]

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1. Univ. Erlangen-Nuernberg, Erlangen (Germany). Inst. fuer Werkstoffwissenschaften

High-temperature X-ray line profile measurements were performed to maximal temperatures of 1,050 C on samples of the nickel-base superalloy SRR 99. The samples with rod axes near the [001] direction were investigated in the initially undeformed state and after creep deformation at different temperatures and stresses. For the measurements of the (002) and (020) line profiles, a special X-ray double crystal diffractometer with negligible line broadening was used which was equipped with a high-temperature vacuum chamber. The line profiles were evaluated for the lattice parameters of the matrix phase {gamma} and the precipitated {gamma}{prime} phase and for values of the lattice mismatch parallel and perpendicular to the stress axis, respectively, which were found to be different. Elastic, tetragonal distortions of the phases {gamma} and {gamma}{prime} could be determined between room temperature and about 900 C. These distortions are thermally induced due to the different thermal expansion coefficients of the two phases and deformation induced due to the different thermal expansion coefficients of the deformation. At the high temperatures of the X-ray measurements, at least partial recovery of the deformation-induced internal stresses occurred, depending on the temperature of the X-ray measurements. The results are discussed and compared with data obtained by complementary techniques.

• Sponsoring Organization: USDOE
• OSTI ID: 250727
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 4 Vol. 27; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
36 MATERIALS SCIENCE
CREEP
DEFORMATION
DISLOCATIONS
GAS TURBINES
INTERFACES
LATTICE PARAMETERS
NICKEL BASE ALLOYS
PRECIPITATION
STRESSES
TEMPERATURE DEPENDENCE
THERMAL EXPANSION
TURBINE BLADES
X-RAY DIFFRACTION