An X-ray study of creep-deformation induced changes of the lattice mismatch in the gamma-prime-hardened monocrystalline nickel-base superalloy SRR 99

Journal Article · Fri Nov 01 04:00:00 EST 1991 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(91)90095-I· OSTI ID:5950133

Kuhn, H -A; Biermann, H; Mughrabi, H; Ungar, T ^[1]

---

1. Erlangen-Nuernberg, Universitaet, Erlangen (West Germany) Eotvos Lorand University, Budapest (Hungary)

In order to measure the local lattice parameters in the gamma-matrix and in the gamma-prime-particles and to obtain information on the lattice mismatch and internal stresses, X-ray line profile measurements were performed on monocrystalline specimens of SRR 99 with axes close to the (001) direction. In the undeformed state these intensity distributions indicate that the local lattice parameters vary spatially in the gamma-phase. For the case of the creep-deformed specimens, whereas the asymmetry of the (020) line profiles was enhanced to the extent that a hump or a second peak appeared, the asymmetry of the (002) line profiles was reversed in sign. A quantitative evaluation yielded mean values of the constrained lattice mismatch which, in the case of creep-deformed specimens, differ significantly for the (001) and (010) lattice plane spacings. It is concluded that the orientation-dependent lattice spacings represent a triaxial state of residual stress which has its origin in the superposition of the originally present coherency stresses and the deformation-induced internal stresses. 32 refs.

• OSTI ID: 5950133
• Journal Information: Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 39; ISSN 0956-7151; ISSN AMATE
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
COHERENT SCATTERING
CREEP
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
CUBIC LATTICES
DEFORMATION
DIFFRACTION
FCC LATTICES
HARDENING
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
LATTICE PARAMETERS
MATERIALS
MECHANICAL PROPERTIES
MONOCRYSTALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
PRECIPITATION HARDENING
RESIDUAL STRESSES
SCATTERING
STRESS ANALYSIS
STRESSES
X-RAY DIFFRACTION