Measurement of the lattice misfit in the single crystal nickel based superalloys CMSX-4, SRR99 and SC16 by convergent beam electron diffraction

Journal Article · Fri Jul 24 00:00:00 EDT 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(98)00085-8· OSTI ID:634676

Voelkl, R ^[1]; Glatzel, U ^[2]; Feller-Kniepmeier, M ^[3]

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1. FH Jena (Germany)
2. Friedrich-Schiller-Univ., Jena (Germany). Inst. f. Materialwissenschaft
3. TU-Berlin (Germany)

Misfit measurements in the nickel based superalloys CMSX-4, SRR99 and SC16 have been performed applying the CBED method. Due to the high lateral resolution of the method, lattice parameters of matrix and {gamma} phase could be measured directly. Use of an incident beam direction {l_angle}1 1 19{r_angle} ensured that even in thin matrix channels the electron beam did not cross the interface and that dynamic effects were minimized. The results showed great differences of misfit values between the dendritic and interdendritic region of the alloys, especially in CMSX-4. At {minus}170 C, CMSX-4 and SRR99 have negative misfit values while the value is positive in SC16. Stress relaxation, respectively, strain relaxation in the thin specimens could be compensated with the help of finite element calculations.

• OSTI ID: 634676
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 12 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DENDRITES
ELECTRON DIFFRACTION
LATTICE PARAMETERS
MICROSTRUCTURE
MONOCRYSTALS
NICKEL BASE ALLOYS