Method of controlling final grain size in supersolvus heat treated nickel-base superalloys and articles formed thereby

US7763129B2 · kind B2 · utility

Assignee

• General Electric Company · US

Inventors

• David Paul Mourer · Danvers, US
• Brian Francis Mickle · Sharonville, US
• Shesh Krishna Srivatsa · Cincinnati, US
• Eric Scott Huron · Marietta, US
• Jon Raymond Groh · Loveland, US
• Kenneth Rees Bain · Loveland, US

Key dates

• Filing date: Apr 18, 2006
• Grant date: Jul 27, 2010
• Expiry date: Feb 4, 2027

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C19/057
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A method of forming a component from a gamma-prime precipitation-strengthened nickel-base superalloy so that, following a supersolvus heat treatment the component characterized by a uniformly-sized grain microstructure. The method includes forming a billet having a sufficiently fine grain size to achieve superplasticity of the superalloy during a subsequent working step. The billet is then worked at a temperature below the gamma-prime solvus temperature of the superalloy so as to form a worked article, wherein the billet is worked so as to maintain strain rates above a lower strain rate limit to control average grain size and below an upper strain rate limit to avoid critical grain growth. Thereafter, the worked article is heat treated at a temperature above the gamma-prime solvus temperature of the superalloy for a duration sufficient to uniformly coarsen the grains of the worked article, after which the worked article is cooled at a rate sufficient to reprecipitate gamma-prime within the worked article.