High temperature brittle intergranular cracking in high strength nickel alloys undoped and doped with S, Zr, and/or B-II. Solute segregation analysis

Journal Article · Mon Feb 01 04:00:00 EST 1993 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(93)90082-4· OSTI ID:6239997

Kameda, J; Bevolo, A J ^[1]

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

In order to clarify the mechanism of high temperature brittle intergranular cracking in high strength nickel alloys, solute segregation at grain boundaries and on high temperature fracture surfaces has been examined by scanning Auger microscopy. Intergranular S segregation producing global embrittling effects was found to increase in the following order: alloys with low S or high S and Zr, high S and B, and high S. The grain boundaries extensively contained Ti or Zr rich sulfides in the S-doped alloys and B segregation inducing intergranular toughening in the alloy with high S and B. The alloys with low S, and high S and B showed more strongly S segregation on high temperature fracture surfaces, which was much greater compared with ,it grain boundaries, than with high S, and high S and Zr. The local stress intensification did not produce at remarkable S enrichment at grain boundaries except near sulfides. It is proposed that S fluxes from crack surfaces and stressed sulfides to the crack tip induce local embrittlement. The composition and temperature effects on the brittle cracking behavior are discussed in terms of the global and local embrittling effects.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6239997
• Journal Information: Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 41:2; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

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