CN-122029052-A - Repair of polycrystalline layers

Abstract

Additive manufacturing of single crystal materials produces polycrystalline layers or grains, which can be reduced or eliminated by treatment with Al or optionally Pt. Thinning of the polycrystalline layer may be performed without mechanical or chemical removal of the polycrystalline material. The workpiece formed by the process may include a monocrystalline substrate, an interdiffusion region on the substrate, and a thermal barrier coating over the interdiffusion region, and the interdiffusion region diffuses the polycrystalline layer such that no post-processing is required to remove the polycrystalline layer.

Inventors

• D. bush
• B. D. Talbot

Assignees

• 蜂巢工业有限公司

Dates

Publication Date

20260512

Application Date

20240919

Priority Date

20230922

Claims (20)

1. 1. A workpiece formed by additive manufacturing, comprising: A monocrystalline substrate, and An inter-diffusion region on the substrate, the inter-diffusion region comprising the same material as the single crystal substrate and an amount of at least one of Al or Pt.
2. 2. The workpiece of claim 1, wherein the inter-diffusion region has a thickness of about 1 μιη to 200 μιη.
3. 3. The workpiece of claim 1, wherein the inter-diffusion region has a thickness of about 1 μιη to 20 μιη.
4. 4. The workpiece of claim 1, wherein the interdiffusion zone comprises a beta phase.
5. 5. The workpiece of claim 1, further comprising a thermal barrier coating formed of ceramic.
6. 6. The workpiece of claim 1, further comprising a thermal barrier coating formed from a ceramic comprising yttria-stabilized zirconia.
7. 7. The workpiece according to claim 6, wherein the yttria-stabilized zirconia contains about 4 to 7 wt% yttria.
8. 8. The workpiece of claim 1, wherein the substrate comprises a nickel alloy.
9. 9. A method for manufacturing a workpiece, comprising: Forming a single crystal substrate by additive manufacturing, the single crystal substrate having a polycrystalline layer, and The polycrystalline layer is treated with at least one of Al or Pt to form an interdiffusion region.
10. 10. The method of claim 9, wherein the treatment of the polycrystalline table is performed by vapor phase aluminizing.
11. 11. The method of claim 9, wherein the treating of the polycrystalline layer is performed by vapor phase aluminizing to form a nickel aluminide comprising at least one of Ni 3 Al, niAl, or NiAl 3 .
12. 12. The method of claim 9, wherein the treating of the polycrystalline layer is performed by vapor phase aluminizing to produce a thickness of the inter-diffusion region of about 1 μιη to 200 μιη.
13. 13. The method of claim 9, wherein the treatment of the polycrystalline layer is performed by vapor phase aluminizing to produce a thickness of the inter-diffusion region of about 1 μιη to 20 μιη.
14. 14. The method of claim 9, wherein the inter-diffusion region comprises a beta phase.
15. 15. The method of claim 9, wherein the single crystal substrate is formed by the sequential steps of: Depositing a powder coating of metal, and Melting the powder coating.
16. 16. The method of claim 9, wherein the polycrystalline table is not thinned by mechanical grinding.
17. 17. The method of claim 9, wherein the polycrystalline layer is not thinned by chemical treatment.
18. 18. The method of claim 9, wherein the polycrystalline layer is treated by mechanical grinding or chemical treatment before or after treating the polycrystalline layer with at least one of Al or Pt.
19. 19. The method of claim 9, further comprising: a thermal bond coating is formed on the interdiffusion region.
20. 20. The method of claim 9, further comprising: A thermal bond coating is formed on the interdiffusion zone, the thermal bond coating comprising at least one material selected from the group consisting of titanium dioxide, zirconium oxide, aluminum oxide, porcelain, mullite, pyrochlore, garnet, monazite, perovskite, and lanthanum magnesium hexaaluminate.

Description

Repair of polycrystalline layers The present application claims priority from U.S. provisional application 63/539,929, entitled "repair of Polymer layer," filed on 9 and 22 of 2023, the entire contents of which are incorporated herein by reference. Technical Field Embodiments relate generally to repair of Polycrystalline (PX) layers produced during additive manufacturing of objects formed from superalloys or steel. Background The Bridgman process is traditionally used to perform the production of high strength and heat resistant single crystal (SX) workpieces, such as turbine blades for aerospace applications. The Bridgman technique involves slowly cooling the molten material by moving a container of the molten material from a hot zone to a cold zone. To promote crystal growth, the end of the vessel where the crystal begins to grow may be elongated and a seed crystal may be placed at that end. The presence of seed crystals requires precise temperature control at the interface and in many cases crystal growth occurs without seed crystals. In the original Bridgman technique, the cold zone is outside the furnace and therefore the temperature gradient is not well defined. The Bridgman technique uses "hot" and "cold" zones to create a temperature differential within the furnace, as shown in fig. 1. The hot zone 10 is maintained at a temperature above the melting point of the material 20. For superalloys, the metal is melted in a separate crucible (not shown). Once the metal is at the correct temperature and the mold 30 is at the correct temperature, molten metal is poured into the mold. The mold has a predetermined shape that is the desired shape of the end use component. The precursor material is a melt in hot zone 10 and is transferred by motion into cold zone 50. The material solidifies 40 as it moves through the temperature gradient in the furnace. The Bridgman method may be performed in a vertical configuration. The improved Bridgman process, known as the Bridgman-stockbar technology, has two well-controlled temperature zones, which are achieved by using two separate ovens with baffles therebetween. Some variations of Bridgman and Bridgman-stockbar techniques include rotation of the vessel and horizontal placement of one or more ovens. Important considerations during crystal growth are the mold material, the temperature of the hot zone, the temperature gradient, and the cooling rate. The container should have minimal reactivity with the sample and withstand the temperature and surrounding environment during growth. In recent years, there has been a great deal of interest in manufacturing SX parts (e.g., turbine blades) using Additive Manufacturing (AM), a modified form of 3-D printing. A diagram of the additive manufacturing process is shown in fig. 2. In fig. 2, powder feeder 110 deposits powder 112 to create powder layer 105 in powder bed 108. The powder layer deposited first may be located directly on the powder bed or on a substrate placed in the powder bed prior to the deposition of the powder layer. The beam scanner 101 may move the beam source 102 or manipulate an energy beam 111 generated by the beam source. The energy beam may be a laser beam, an electron beam, or the like. The energy beam 111 creates the melt pool 104, wherein the energy beam 111 melts some of the powder in the powder bed 108. The melt pool 104 has a melt pool depth 103. The melt pool depth 103 is shown to be large enough to also melt some of the patterned layer 106 directly below the powder layer 105. The beam scanner moves the melt pool 104 in a path through the topmost powder layer to selectively melt some of the powder, thereby creating a patterned layer. The powder layer deposited first becomes the bottom patterned layer 107. The 3D object is printed by iteratively depositing a powder layer and fusing a pattern into the powder layer using an energy beam, resulting in a patterned layer. Fig. 3 is a high-level conceptual diagram illustrating a scan pattern 200 with a melt pool 104 and a hatch distance 203 according to some aspects. The scan pattern 200 may include a large number of scan lines 201 that may be parallel to each other, as shown in fig. 3. The hatching distance 203 is a distance between the scan lines 201. The hatching direction is a direction from a previous scanning line to a subsequent scanning line in the scanning pattern. The hatched direction 204 may be perpendicular to the scan line 201. The beam scanner moves the melt pool 104 along the scan pattern. For simplicity, the melt pool is shown as a circle, with the energy beam 111 contacting the powder layer and melting the powder at that location. In practice, the melt pool is much longer because the energy beam melts the material in a pattern and the melted material remains molten for a short period of time. That is, laser powder bed melting AM of metals such as steel and nickel superalloys is performed in a protective chamber with a dynamic flow of inert gas (