High temperature brittle intergranular cracking in high strength nickel alloys undoped and doped with S, Zr and/or B-I. Crack growth characteristics

Journal Article · Mon Feb 01 00:00:00 EST 1993 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(93)90081-3· OSTI ID:6268936

Kameda, J ^[1]

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1. Iowa State Univ., Ames, IA (United States). Ames Lab.

High temperature (823-923 K) brittle intergranular cracking behavior has been studied in [gamma][prime] strengthening nickel alloys doped with and without S, B and/or Zr. The growth rate of brittle intergranular cracks was found to be described by da/dt =[dot a][sub 0](K/K[sub 0])[sup n] where K[sub 0] and [dot a][sub 0] represent a transition from the crack nucleation to growth controlling process. The alloy composition and temperature produced quite different effects on K[sub 0] and n. In undoped and S-doped alloys, high temperature cracking occurred at the lowest K[sub 0] which strongly depends on the temperature. However, the undoped and S-doped alloys exhibited the lowest and highest values of n, respectively, almost independent of the temperature. The addition of B increased K[sub 0] and decreased n more greatly than that of Zr in alloys with high S. The alloy with high S and Zr showed the strongest temperature dependence of n in all the alloys. It has been shown by estimating the activation energy from the Arrhenius plot of [dot a][sub 0] that the brittle intergranular cracking behavior is controlled by S diffusion at grain boundaries and on crack surfaces.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6268936
• Journal Information: Acta Metallurgica et Materialia; (United States), Vol. 41:2; ISSN 0956-7151
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
NICKEL BASE ALLOYS
CRACK PROPAGATION
BORON ADDITIONS
BRITTLENESS
GRAIN BOUNDARIES
SULFUR ADDITIONS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
ZIRCONIUM ADDITIONS
ALLOYS
BORON ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL ALLOYS
TEMPERATURE RANGE
ZIRCONIUM ALLOYS
360103* - Metals & Alloys- Mechanical Properties