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

The patent describes an alloy that includes a matrix phase and a population of particulate phases dispersed within the matrix. The matrix includes iron and chromium, and the particulate phases include a complex oxide and a Laves phase. The complex oxide has a small size and is present in a small amount in the alloy, while the Laves phase has a larger size and is present in a larger amount. The alloy can be formed by melting and atomizing the starting materials, and then consolidating and precipitating the particulate phases at a specific temperature. The technical effect of this alloy is that it has improved properties, such as high strength and good corrosion resistance.

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 efficiency of the turbine and increase the cost.

However, conventional steels cannot currently be used in high temperature and high stress applications because they do not meet the necessary mechanical property requirements.