Components formed by controlling grain size in forged precipitation-strengthened alloys

摘要

Components and methods of processing such components from precipitation-strengthened alloys so that the components exhibit desirable grain sizes following a supersolvus heat treatment. The method includes consolidating a powder of the alloy to form a billet having an average grain size. The billet is then forged at a temperature below the solvus temperature to form a forging having an average grain size of not coarser than the grain size of the billet. The billet is then forged at a total strain of at least 5%, after which at least a portion of the forging is heat treated at a temperature below the solvus temperature to pin grains within the portion. The entire forging can then be heat treated at a temperature above the solvus temperature of the alloy without coarsening the grains in the portion.

主权项

1. An article having first and second portions, the article being produced by a method comprising:
forming a powder of a precipitation-strengthened iron-based or nickel-based superalloy having a solvus temperature consolidating the powder at a temperature below the solvus temperature of the superalloy to form a billet having an average grain size; forging the billet at a temperature below the solvus temperature of the superalloy to form a forging comprising the first and second portions of the article, the forging having an average grain size of not coarser than the average grain size of the billet, the billet being forged so as to achieve a total strain of at least 5%; heat treating at least the first portion of the forging, but not the second portion of the forging, at a temperature below the solvus temperature of the superalloy to pin grains within the first portion; heat treating the forging in its entirety at a temperature above the solvus temperature of the superalloy to solution precipitates in the forging without coarsening the grains in the first portion, wherein grains in the second portion are coarsened to an average grain size of coarser than the average grain size of the billet; and cooling the forging, wherein the average grain size within the first portion is within 1 or 2 ASTM sizes of the average grain size of the billet.