Twin formation during creep in single crystals of nickel-based superalloys

Journal Article · Fri Jul 09 04:00:00 EDT 1999 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(99)00145-7· OSTI ID:6337757

Ardakani, M G; McLean, M; Shollock, B A ^[1]

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1. Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials

A detailed study has been made of the evolution in orientations of single crystal nickel-based superalloys creep tested in tension to fracture in the stress range 200--850 MPa and temperature range 750--1,050 C. Overall rotations from the initial tensile axis along the gauge length as well as localized changes in orientation have been evaluated. Specimens of SRR99 with nominal axial orientations of [001], [111] and [011] and of CMSX-4 with [111] and [011] orientations have been considered. Electron back scattered diffraction (EBSD) analyses of [011] and [111] crystals tested at relatively high stresses (> 450 MPa) show highly deformed regions ([approximately]1 [micro]m lateral dimension) that are oriented at 60[degree] rotation about <111>. Transmission electron microscopy (TEM) confirms that this orientation relationship arises from twinning. These features are not observed for [001] specimens.

• OSTI ID: 6337757
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Vol. 47:9; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals &amp; Alloys-- Structure &amp; Phase Studies
360103 -- Metals &amp; Alloys-- Mechanical Properties
ALLOYS
CREEP
CRYSTALS
ELECTRON MICROSCOPY
MECHANICAL PROPERTIES
MICROSCOPY
MICROSTRUCTURE
MONOCRYSTALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K
TRANSMISSION ELECTRON MICROSCOPY
TWINNING
VERY HIGH PRESSURE