Method of preparing a surface for diffusion bonding and method of diffusion bonding

Patent metadata

Field	Value
Publication number	US-11298768-B2
Application number	US-201916684974-A
Country	US
Kind code	B2
Filing date	Nov 15, 2019
Priority date	Nov 15, 2019
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

A method of preparing a surface for diffusion bonding comprises contacting a binder material with a discontinuous surface comprising surface regions separated by gaps. The binder material is selectively deposited onto the surface regions and has a sufficient viscosity to form a self-supporting layer without flowing into the gaps. The self-supporting layer of binder material comprises a mass density in a range from about 0.001 g/in2 to about 0.050 g/in2. A braze powder is distributed over the self-supporting layer of binder material, and a predetermined amount of the braze powder is attached to the binder material. The discontinuous surface is then heated to remove the binder material and adhere the braze powder to the discontinuous surface. Thus, a prewet surface with a braze deposit thereon is formed.

First claim

What is claimed is:

1. A method of preparing a surface for diffusion bonding, the method comprising:
contacting a binder material with a discontinuous surface comprising surface regions separated by gaps, the binder material being selectively deposited onto the surface regions and forming a self-supporting layer without flowing into the gaps, the self-supporting layer of binder material being uniformly deposited on the surface regions with a mass density in a range from about 0.001 g/in 2 to about 0.050 g/in 2 , wherein the contacting comprises rolling a belt or roller coated with the binder material over the discontinuous surface, an axis of rotation of the belt or roller being parallel to the surface regions;
distributing a braze powder over the binder material, a predetermined amount of the braze powder being attached to the binder material; and
heating the discontinuous surface to remove the binder material and adhere the braze powder to the discontinuous surface, thereby forming a prewet surface with a braze deposit thereon.

2. The method of claim 1 , wherein the predetermined amount of braze powder lies in a range from about 0.04 g/in 2 to about 0.250 g/in 2 , and wherein the braze deposit comprises the predetermined amount of braze powder.

3. The method of claim 1 , wherein the belt or roller comprises a surface roughness in a range from about 16 rms to about 63 rms.

4. The method of claim 1 , wherein the binder material comprises a polymer selected from the group consisting of cyanoacrylate polymers and acrylic polymers.

5. The method of claim 1 , wherein binder material comprises a cyanoacrylate polymer or an acrylic polymer.

6. The method of claim 1 , wherein the discontinuous surface is heated to a temperature at or above a sintering temperature of the braze powder and below a melting temperature of the braze powder.

7. The method of claim 6 , wherein the temperature is in a range from about 100° F. below a solidus to about 30° F. above a liquidus of the braze powder.

8. The method of claim 1 , wherein removing the binder material comprises pyrolyzing or vaporizing the binder material.

9. The method of claim 1 , wherein the heating is carried out in a vacuum or an inert gas atmosphere.

10. The method of claim 1 , wherein the discontinuous surface is part of a first component comprising a metal alloy.

11. The method of claim 10 , wherein first component comprises a nickel-base alloy and the braze powder comprises nickel alloyed with boron and/or chromium.

12. The method of claim 10 , wherein the first component comprises a titanium-base alloy and the braze powder comprises titanium alloyed with copper, nickel, and/or zirconium.

13. The method of claim 1 , wherein the braze powder comprises particles having a particle size in a range from about 44 microns to 63 microns.

14. The method of claim 1 , wherein the braze powder comprises particles having a spheroidal, spherical, polygonal, elongated, or irregular morphology.

15. A method of diffusion bonding comprising:
assembling a first component comprising the prewet surface of claim 1 with a second component comprising a mating surface to form an assembly, the braze deposit on the prewet surface contacting the mating surface; and
exposing the assembly to a bonding temperature and a compressive force, thereby diffusion bonding the first component to the second component to form a monolithic third component comprising a bonded interface.

16. The method of claim 15 , wherein the monolithic third component comprises an airfoil, a combustion liner, a heat shield, or another gas turbine engine component.

17. The method of claim 15 , wherein the first component comprises a spar and the second component comprises a coversheet.

18. The method of claim 15 , wherein the first and second components have a single-crystalline structure, and wherein a directionally solidified microstructure is obtained across the bonded interface.

19. The method of claim 15 , wherein the bonding temperature lies in a range from about 900° C. to about 1275° C.

Assignees

• Rolls Royce Corp

Inventors

• Fuesting Timothy
• Henderkott Joseph P

Classifications

• B23K2103/14

  Titanium or alloys thereof · CPC title

• B23K20/24

  Preliminary treatment · CPC title

• B23K35/325

  Ti as the principal constituent · CPC title

• B23K35/0244

  Powders, particles or spheres; Preforms made therefrom · CPC title

• B22F7/08

  with one or more parts not made from powder {(B22F7/062 takes precedence)} · CPC title