Method for minimizing nonuniform nucleation and supersolvus grain growth in a nickel-base superalloy
US5529643A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1994 |
| Grant date | Jun 25, 1996 |
| Priority date | — |
| Expiry date | Oct 17, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22F1/10
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method is provided for obtaining uniform grain growth within .gamma.' precipitation strengthened nickel-base superalloys. The method includes forming a billet having a very fine grain size in order to achieve optimum superplasticity of the superalloy during forging. The article is then heated to a pre-working hold temperature in a manner which prevents coarsening of the microstructure and a loss of superplasticity. The article is then worked, such as by forging, at a temperature below the .gamma.' solvus temperature of the alloy, so as to maintain local strain rates within the article below a critical strain rate for random grain growth, and so as to maintain the strain rate gradient throughout the article below a critical upper limit. After working, the article is subjected to annealing at a temperature which is less than the .gamma.' solvus temperature of the alloy, and for a duration which is sufficient to remove accumulated metallurgical strain in the article. A supersolvus heat treatment is then performed by further heating the article to a temperature above the .GAMMA.' solvus temperature of the superalloy for a duration sufficient to uniformly coarsen the grains of the art…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.