Precipitate strengthened nanostructured ferritic alloy and method of forming

Abstract

An alloy and method of forming the alloy are provided. The alloy includes a matrix phase, and a population of particulate phases dispersed within the matrix. The matrix includes iron and chromium; and the population includes a first subpopulation of particulate phases and a second subpopulation of particulate phases. The first subpopulation of particulate phases include a complex oxide, having a median size less than about 20 nm, and present in the alloy in a concentration from about 0.1 volume percent to about 5 volume percent. The second subpopulation of particulate phases have a median size in a range from about 30 nm to about 10 microns, and present in the alloy in a concentration from about 1 volume percent to about 15 volume percent.

Description

BACKGROUND[0001]The invention relates generally to a nanostructured ferritic alloy. More particularly the invention relates to a nanostructured ferritic alloy having dual scale dispersions.[0002]Gas turbines operate in extreme environments, exposing the turbine components, especially those in the turbine hot section, to high operating temperatures and stresses. In order for the turbine components to endure these conditions, they are manufactured from a material capable of withstanding these severe conditions. As material limits are reached, one of two approaches is conventionally used in order to maintain the mechanical integrity of hot section components. In one approach, cooling air is used to reduce the part's effective temperature. In a second approach, the component size is increased to reduce the stresses. However, these approaches can reduce the efficiency of the turbine and increase the cost.[0003]In certain applications, super alloys have been used in these demanding applic...

AI Technical Summary

Benefits of technology

[0006]In one embodiment, an alloy is provided. The alloy includes a matrix phase, and a population of particulate phases dispersed within the matrix. The matrix includes iron and chromium; and the population includes a first subpopulation of particulate phases and a second subpopulation of particulate phases. The first subpopulation of particulate phases include a complex oxide, having a median size less than about 20 nm, and present in the alloy in a concentration from about 0.1 volume percent to about 5 volume percent. The second subpopulation of particulate phases have a median size in a range from about 30 nm to about 10 microns, and present in the alloy in a concentration from about 1 volume percent to about 15 volume percent.

[0007]In one embodiment, an alloy is provided. The alloy includes a matrix phase, and a population of particulate phases dispersed within the matrix. The matrix includes iron and chromium; and the population includes a first subpopulation of particulate phases and a second subpopulation of particulate phases. The first subpopulation of particulate phases include a complex oxide having yttrium and titanium, and having a median size less than about 10 nm, and present in the alloy in a concentration from about 0.1 volume percent to about 3 volume percent. The second subpopulation of particulate phases include precipitated Laves phase, have a median size in a range from about 50 nm to about 3 microns, and present in the alloy in a concentration from about 1 volume percent to about 6 volume percent.

[0008]In one embodiment, a method of forming an alloy is provided. The method includes melting starting materials comprising iron and chromium; atomizing the melt to form an alloy powder; milling the alloy...

Problems solved by technology

Gas turbines operate in extreme environments, exposing the turbine components, especially those in the turbine hot section, to high operating temperatures and stresses.

However, these approaches can reduce the effi...