Controlled Grain Microstructures in Cast Alloys

Patent metadata

Field	Value
Publication number	US-2021069777-A1
Application number	US-201916593423-A
Country	US
Kind code	A1
Filing date	Oct 4, 2019
Priority date	Oct 5, 2018
Publication date	Mar 11, 2021
Grant date	—

Abstract

Methods for creating a cast component, along with the resulting cast components, are provided. The method may provide for a controlled grain structure in the resulting cast component. The methods may include heating at least a first portion mold under controlled conditions, such as when the first portion of the mold is buried in a ceramic powder.

First claim

What is claimed is:

1 . A method of creating a cast alloy component from a metal material having a solidus temperature and a liquidus temperature, comprising:
burying at least a first portion of a mold in a powder of ceramic material; heating the mold within the powder of ceramic material; thereafter, pouring molten metal material into the mold while the first portion is buried in the powder of ceramic material; and thereafter, allowing the molten metal material to form the cast alloy component within the mold while the first portion is buried within the powder of ceramic material.

2 . The method of claim 1 , wherein:
burying at least a first portion of a mold in a powder of ceramic material comprises: burying the mold in a powder of ceramic material; heating the mold within the powder of ceramic material comprises: heating the mold within the powder of ceramic material to an initial mold temperature that is 50% or less of the solidus temperature of the metal material; pouring molten metal material into the mold while the first portion is buried in the powder of ceramic material comprises: pouring molten metal material into the mold buried within the powder of ceramic material; and allowing the molten metal material to form the cast alloy component within the mold while the first portion is buried within the powder of ceramic material comprises: allowing the molten metal material to form the cast alloy component within the mold buried within the powder of ceramic material.

3 . The method of claim 1 , wherein the cast alloy component has a grain size of 250 micrometers or less, and wherein the powder of ceramic material comprises alumina, zirconia, hafnia, titania, silica, cobalt aluminate, zircon, silica, magnesia, a rare earth oxide, or a mixture thereof.

4 . The method of claim 1 , wherein the molten metal material is poured into the mold while in a chamber defined within a vacuum induction melter, wherein the chamber of the vacuum induction melter has an atmosphere having a pressure of that is less than 1 atm.

5 . The method of claim 4 , wherein allowing the molten metal material to form the cast alloy component comprises:
removing the mold buried within the powder of ceramic material from the vacuum induction melter after the molten metal material is poured therein; allowing the molten metal material to heat the mold while buried within the powder of ceramic material until the molten metal material is completely solidified within the mold; and thereafter, removing the mold from the powder of ceramic material and allowing the mold to cool.

6 . The method of claim 5 , wherein
allowing the mold to cool is performed while subjecting the mold to an overpressure.

7 . The method of claim 1 , wherein:
heating the mold within the powder of ceramic material comprises: heating the mold under controlled conditions such that the first portion of the mold has a first thermal condition and a second portion of the mold has a second thermal condition that is different than the first thermal condition; and pouring molten metal material into the mold while the first portion is buried in the powder of ceramic material comprises: pouring molten metal material into the mold such that the molten metal material fills the first portion and the second portion of the mold.

8 . The method of claim 1 , wherein:
burying at least a first portion of a mold in a powder of ceramic material comprises: surrounding the first portion of the mold in the powder of ceramic material while leaving a second portion of the mold exposed.

9 . The method of claim 7 , wherein the mold is heated such that the first portion has an initial first portion temperature and such that the second portion has an initial second temperature that is different than the initial first portion temperature.

10 . The method of claim 7 , wherein the initial second temperature is greater than the initial first portion temperature.

11 . The method of claim 7 , wherein the cast component has a first section corresponding to the first portion of the mold and having a first average grain size therein, and wherein the cast component has a second section corresponding to the second portion of the mold and having a second average grain size therein; wherein the first average grain size is less than the second average grain size.

12 . The method of claim 7 , further comprising:
cooling an edge of the second portion of the mold, wherein the edge of the second portion of the mold is cooled such that a temperature gradient exists within the second portion of the mold.

13 . The method of claim 7 , wherein the cast component has a first section corresponding to the first portion of the mold and having a first average grain size therein, and wherein the cast component has a second section corresponding to the second portion of the mold and having a second average grain size therein; wherein the second average grain size has a higher average aspect ratio than the first average grain size, and wherein the second average grain size is more columnar than the first average grain size.

14 . The method of claim 7 , wherein the metal material is an alloy or a superalloy, wherein the mold is constructed from a ceramic material, and wherein the ceramic material of the mold has a different composition than the ceramic material of the powder.

15 . A cast component comprising a metal alloy, wherein the cast component defines a first section having first grains with a first average grain size and a second section having second grains with a second average grain size, wherein the first average grain size is less than the second average grain size, wherein the second grains have an average second aspect ratio that is greater than an average first aspect ratio of the first grains.

16 . The cast component of claim 15 , further defining a third section having third grains with a third average grain size, wherein the third average grain size is greater than the first average grain size.

17 . The cast component of clause 16 , wherein the third average grain size is less than the second average grain size.

18 . A bladed disk comprising an internal disk having a plurality of airfoils extending radially outward therefrom, wherein the bladed disk comprises a cast metal alloy having a plurality of first grains with a first average grain size within the internal disk and a plurality of second grains with a second average grain size within the plurality of airfoils, wherein the first average grain size is less than the second average grain size.

19 . The bladed disk of claim 18 , wherein the cast metal alloy further has a plurality of third grains with a third average grain size in a transition section between the internal disk and the plurality of airfoils, wherein the third average grain size is larger than the first average grain size.

Assignees

• Gen Electric

Inventors

• Przeslawski Brian David
• Acosta Manuel
• Konitzer Douglas Gerard
• Miller Joshua Leigh
• Makinde Adegboyega Masud

Classifications

• F01D5/147

  Construction, i.e. structural features, e.g. of weight-saving hollow blades (F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18) · CPC title

• B22D15/00 Primary

  Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor · CPC title

• B22D27/045

  Directionally solidified castings · CPC title

• B22C9/04 Primary

  Use of lost patterns · CPC title

• B22D21/025

  Casting heavy metals with high melting point, i.e. 1000 - 1600 degrees C, e.g. Co 1490 degrees C, Ni 1450 degrees C, Mn 1240 degrees C, Cu 1083 degrees C · CPC title