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Title: Method of improving fatigue life of cast nickel based superalloys and composition

Abstract

The invention consists of a method of producing a fine equiaxed grain structure (ASTM 2-4) in cast nickel-base superalloys which increases low cycle fatigue lives without detrimental effects on stress rupture properties to temperatures as high as 1800.degree. F. These superalloys are variations of the basic nickel-chromium matrix, hardened by gamma prime [Ni.sub.3 (Al, Ti)] but with optional additions of cobalt, tungsten, molybdenum, vanadium, columbium, tantalum, boron, zirconium, carbon and hafnium. The invention grain refines these alloys to ASTM 2 to 4 increasing low cycle fatigue life by a factor of 2 to 5 (i.e. life of 700 hours would be increased to 1400 to 3500 hours for a given stress) as a result of the addition of 0.01% to 0.2% of a member of the group consisting of boron, zirconium and mixtures thereof to aid heterogeneous nucleation. The alloy is vacuum melted and heated to 250.degree.-400.degree. F. above the melting temperature, cooled to partial solidification, thus resulting in said heterogeneous nucleation and fine grains, then reheated and cast at about 50.degree.-100.degree. F. of superheat. Additions of 0.1% boron and 0.1% zirconium (optional) are the preferred nucleating agents.

Inventors:
 [1];  [2];  [3]
  1. Chardon, OH
  2. Cleveland, OH
  3. Shaker Heights, OH
Issue Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
OSTI Identifier:
863029
Patent Number(s):
4078951
Application Number:
05/672,350
Assignee:
University Patents, Inc. (Stamford, CT)
Patent Classifications (CPCs):
C - CHEMISTRY C22 - METALLURGY C22F - CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
method; improving; fatigue; life; cast; nickel; based; superalloys; composition; consists; producing; fine; equiaxed; grain; structure; astm; 2-4; nickel-base; increases; cycle; lives; detrimental; effects; stress; rupture; properties; temperatures; 1800; degree; variations; basic; nickel-chromium; matrix; hardened; gamma; prime; optional; additions; cobalt; tungsten; molybdenum; vanadium; columbium; tantalum; boron; zirconium; carbon; hafnium; refines; alloys; increasing; factor; 700; hours; increased; 1400; 3500; result; addition; 01; consisting; mixtures; heterogeneous; nucleation; alloy; vacuum; melted; heated; 250; -400; melting; temperature; cooled; partial; solidification; resulting; grains; reheated; 50; -100; superheat; preferred; nucleating; agents; nickel base; gamma prime; optional additions; melting temperature; stress rupture; nickel-base superalloy; nucleating agents; fine grain; fatigue life; grain structure; rupture properties; nickel based; nucleating agent; cast nickel; cast nickel-base; /148/75/420/

Citation Formats

Denzine, Allen F, Kolakowski, Thomas A, and Wallace, John F. Method of improving fatigue life of cast nickel based superalloys and composition. United States: N. p., 1978. Web.
Denzine, Allen F, Kolakowski, Thomas A, & Wallace, John F. Method of improving fatigue life of cast nickel based superalloys and composition. United States.
Denzine, Allen F, Kolakowski, Thomas A, and Wallace, John F. Tue . "Method of improving fatigue life of cast nickel based superalloys and composition". United States. https://www.osti.gov/servlets/purl/863029.
@article{osti_863029,
title = {Method of improving fatigue life of cast nickel based superalloys and composition},
author = {Denzine, Allen F and Kolakowski, Thomas A and Wallace, John F},
abstractNote = {The invention consists of a method of producing a fine equiaxed grain structure (ASTM 2-4) in cast nickel-base superalloys which increases low cycle fatigue lives without detrimental effects on stress rupture properties to temperatures as high as 1800.degree. F. These superalloys are variations of the basic nickel-chromium matrix, hardened by gamma prime [Ni.sub.3 (Al, Ti)] but with optional additions of cobalt, tungsten, molybdenum, vanadium, columbium, tantalum, boron, zirconium, carbon and hafnium. The invention grain refines these alloys to ASTM 2 to 4 increasing low cycle fatigue life by a factor of 2 to 5 (i.e. life of 700 hours would be increased to 1400 to 3500 hours for a given stress) as a result of the addition of 0.01% to 0.2% of a member of the group consisting of boron, zirconium and mixtures thereof to aid heterogeneous nucleation. The alloy is vacuum melted and heated to 250.degree.-400.degree. F. above the melting temperature, cooled to partial solidification, thus resulting in said heterogeneous nucleation and fine grains, then reheated and cast at about 50.degree.-100.degree. F. of superheat. Additions of 0.1% boron and 0.1% zirconium (optional) are the preferred nucleating agents.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1978},
month = {3}
}

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