A Ti60 / tantalum tungsten alloy multistage thermal structural material based on Ta10W@Ta core-shell engineering powder and a laser directed energy deposition manufacturing method thereof

Abstract

The application discloses a kind of Ti60 / tantalum-tungsten alloy multistage thermal structural materials based on Ta10W@Ta core-shell engineering powder and laser directional energy deposition manufacturing method, belong to laser directional energy deposition additive manufacturing technical field.The method with Ti60 titanium alloy as matrix, with Ta10W@Ta core-shell engineering powder as powder feeding material, forms Ta10W deposition layer on the surface of substrate by laser directional energy deposition.The Ta10W@Ta core-shell engineering powder is formed by ball milling, adhesive bonding and diffusion sintering, wherein Ta10W alloy particles are used as core, Ta is used as outer shell layer, the thickness of Ta shell layer is 0.2-3 μm, the particle size D50 of Ta10W core powder is 45 μm, and the particle size D50 of Ta shell powder is 5 μm.Ta outer shell layer preferentially participates in melting at the initial stage of deposition, and forms Ta enrichment area near the overall connecting interface between deposition body and Ti60 titanium alloy matrix, thereby forming a multistage interface transition structure including Ta10W deposition layer, Ta enrichment reaction inhibition transition zone, Ti-Ta mixed transition zone and heat affected zone.The method is suitable for local manufacturing or repairing of high-temperature load-bearing components.

Description

Technical Field

[0001] This invention belongs to the field of laser-directed energy deposition additive manufacturing technology, specifically relating to a multi-level thermal structure material and its manufacturing method for bonding titanium alloys and tantalum-tungsten alloys, based on Ta-W@Ta core-shell engineering powder to achieve time-sequential release control of W element. Specifically, this invention relates to a Ti60 / tantalum-tungsten alloy multi-level thermal structure material based on Ta10W@Ta core-shell engineering powder and its laser-directed energy deposition manufacturing method. Background Technology

[0002] Ti60 titanium alloy possesses high specific strength and excellent high-temperature service performance, making it valuable for applications in high-temperature load-bearing components in aerospace. Ta10W alloy combines a high melting point, good high-temperature stability, and ablation resistance, making it suitable as a localized high-temperature functional layer material. However, directly joining Ti60 titanium alloy and Ta10W alloy via laser-directed energy deposition often leads to unstable metallurgical reactions and significant thermal stress concentration at the interface due to differences in thermophysical properties, melting behavior, and abrupt changes in element diffusion paths.

[0003] Existing dissimilar metal joining methods typically mitigate interfacial reactions by using independent intermediate layers, gradient transition layers, or surface modification. While these methods can improve joint formation quality to some extent, they still suffer from complex processes, increased number of interfaces, and difficulty in stabilizing and controlling the reaction layer. For the Ti60 / Ta10W system, if the Ti60 side is directly exposed to a high concentration of W during the initial deposition phase, it may still induce unfavorable interfacial reactions and increase crack susceptibility.

[0004] Laser-directed energy deposition (LMD) offers advantages such as adjustable heat input, flexible forming area, and suitability for localized manufacturing or repair. However, relying solely on adjusting parameters like laser power, scanning speed, and preheating temperature makes it difficult to fundamentally alter the elemental contact sequence at the initial stage of the Ti60 / Ta10W interface. Therefore, it remains necessary to propose an interface control scheme based on core-shell powder feeding material design for the transition manufacturing between the Ti60 substrate and the Ta10W deposited layer. Summary of the Invention

[0005] This invention aims to address the problems of severe interfacial reactions, thermal stress concentration, and high crack susceptibility during the laser-directed energy deposition (LDED) bonding process of Ti60 titanium alloy and Ta10W alloy. It provides a multi-level thermal structure material of Ti60 / tantalum-tungsten alloy based on Ta10W@Ta core-shell engineering powder and its laser-directed energy deposition manufacturing method. This method, through synergistic control of the powder feed material structure and deposition heat input, allows the Ta outer shell layer to preferentially participate in melting during the initial deposition stage, achieving delayed release of W elements in the molten pool, thereby forming a controlled interfacial transition structure between the Ti60 substrate and the Ta10W deposition layer.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A laser-directed energy deposition method for manufacturing Ti60 / tantalum-tungsten alloy multi-level thermal structure materials based on Ta10W@Ta core-shell engineering powder includes the following steps:

[0008] (1) Substrate preparation: Ti60 titanium alloy was selected as the substrate material. The surface of the area to be deposited was cleaned, degreased and pretreated to improve the bonding stability between the deposited layer and the substrate.

[0009] (2). Preparation of core-shell engineering powder: Ta10W alloy powder was selected as the core powder and Ta powder as the outer shell powder. A Ta outer coating layer was formed on the surface of the Ta10W powder by ball milling, adhesion bonding, and diffusion sintering to obtain Ta10W@Ta core-shell engineering powder. The Ta shell layer is a continuous or semi-continuous coating layer with a thickness of 0.2–3 μm; the particle size D50 of the Ta10W core powder is 45 μm, and the particle size D50 of the Ta shell powder is 5 μm.

[0010] (3) Laser-Directed Energy Deposition (LMD) Connection: The Ta-W@Ta core-shell engineering powder is delivered to the surface of the titanium alloy substrate or the joint area using laser-directed energy deposition (LMD) technology to form a tantalum-tungsten alloy deposition layer. During the deposition process, under the action of the laser heat source, the Ta outer shell preferentially participates in melting and forms a Ta-enriched region near the interface. Subsequently, the Ta-W core gradually participates in melting, thereby regulating the release and mass transfer process of W element.

[0011] (4) Process parameter control: Ar protective atmosphere and substrate preheating conditions were used for pass-by-pass and layer-by-layer deposition. The laser power was 2.5kW, the scanning speed was 10mm / s, the powder feed rate was 12g / min, the spot diameter was 0.8-3.0mm, the interpass overlap rate was 30%-60%, the layer thickness was 0.2-0.8mm, and the substrate preheating temperature was 350℃.

[0012] (5) Interface structure regulation: During the deposition process, the Ta shell melts preferentially and forms a Ta-enriched region near the interface between the deposit and the Ti60 titanium alloy matrix. Subsequently, the Ta10W core gradually participates in melting and mass transfer, thereby forming a multi-level interface transition structure near the overall interface, including the Ta10W deposit layer, the Ta enrichment reaction inhibition transition zone, the Ti-Ta mixing transition zone, and the heat-affected zone.

[0013] (6) Post-treatment: After deposition, the deposition area is subjected to heat treatment, machining or surface finishing to obtain Ti60 / tantalum-tungsten alloy multi-level thermal structure material.

[0014] Furthermore, the “W delayed release regulation region” or “Ta-based diffusion barrier region” shown in the attached figure is a schematic representation of the mechanism, used to characterize the regulation effect of the Ta shell layer on the W diffusion / release timing in the core, and is not limited to an independent entity layer physically separated from the Ta shell layer.

[0015] Furthermore, the deposition path employs a short-track partitioning combined with staggered scanning to perform layer-by-layer deposition.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) By constructing Ta10W@Ta core-shell engineering powder, the Ta outer shell layer preferentially participates in melting in the early stage of deposition, thereby forming a Ta-enriched interface transition environment between the Ti60 side and the Ta10W deposition layer;

[0017] (2) Through the synergistic control of Ta10W@Ta core-shell engineering powder and LMD process parameters, a multi-level partitioned structure consisting of Ta10W deposition layer, Ta enrichment reaction inhibition transition zone, Ti-Ta mixing transition zone and heat-affected zone can be formed near the overall connection interface between the deposit and Ti60 matrix.

[0018] (3) The present invention can achieve the interface transition control between Ti60 and Ta10W by using a single powder feeding system. The process path is relatively simplified and it is suitable for the local manufacturing or repair of high temperature load-bearing components. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the single-particle structure of Ta10W@Ta core-shell engineering powder in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the Ta10W@Ta core-shell engineering powder preparation process in an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the time-series melting mechanism of Ta10W@Ta core-shell engineering powder during laser-directed energy deposition in an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the partitioned structure of the overall connection interface between the deposited body and the Ti60 titanium alloy substrate in an embodiment of the present invention.

[0023] Wherein: 1-Ta shell; 2-W delayed release regulation zone (schematic); 3-Ta10W core; 4-Ta10W deposition layer; 5-Ta enrichment reaction inhibition transition zone; 6-Ti-Ta mixed transition zone; 7-heat affected zone; 8-Ti60 titanium alloy matrix layer; 9-Ta10W@Ta core-shell engineering powder. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings. It should be understood that the following embodiments are only for explaining the present invention and are not intended to limit the scope of protection of the present invention. All equivalent substitutions or modifications made based on the concept of the present invention should fall within the scope of protection of the present invention.

[0025] In one embodiment, the present invention uses Ti60 titanium alloy as the substrate and Ta10W@Ta core-shell engineering powder as the powder feeding material. A Ta10W deposition layer is formed on the substrate surface using laser-directed energy deposition (LMD) technology, and a multi-level interface transition structure is constructed between the deposit and the substrate.

[0026] like Figure 1 As shown, the Ta10W@Ta core-shell engineering powder comprises a Ta10W alloy core and an outer Ta shell layer; the Ta shell layer is a continuous or semi-continuous coating layer with a thickness of 0.2–3 μm. The “W delayed release regulation region (schematic)” marked in the figure is used to characterize the regulation effect of the Ta shell layer on the diffusion / release timing of W element in the core under laser irradiation, and is not limited to an independent solid layer separated from the Ta shell layer.

[0027] like Figure 2 As shown, the Ta10W@Ta core-shell engineering powder is obtained by ball milling, adhesion bonding, diffusion sintering, wherein Ta10W alloy powder is used as the core powder and Ta powder is used as the outer shell powder; the particle size D50 of the Ta10W core powder is 45μm and the particle size D50 of the Ta shell powder is 5μm.

[0028] like Figure 3 and Figure 4 As shown, the method of the present invention may include the following steps:

[0029] S1 Substrate Preparation and Additive Manufacturing Area Determination: Ti60 titanium alloy substrate was selected as the deposition substrate. The additive manufacturing area and deposition range were determined based on the geometry of the component to be manufactured or the area to be repaired. The substrate surface was ground, sandblasted, or lightly mechanically roughened, and then degreased and cleaned with acetone, ethanol, or other cleaning media. Drying and dehumidification were performed if necessary to reduce the adverse effects of surface contamination on the interfacial metallurgical bonding.

[0030] S2 Core-Shell Powder Design and Selection: Ta10W@Ta core-shell engineering powder is selected as the powder feed material, wherein Ta10W alloy forms the core and Ta forms the outer shell. The Ta shell is formed on the surface of the Ta10W core through ball milling, adhesion bonding, and diffusion sintering. In a preferred embodiment, the core powder is Ta10W powder. The shell preferentially participates in melting during the initial deposition stage, thereby facilitating the initial formation of a Ta-rich liquid phase environment within the molten pool.

[0031] S3 Deposition Environment Establishment: A coaxial powder feeding LMD process was used to establish an Ar protective environment in the deposition area; the Ti60 titanium alloy substrate was preheated to 350℃ before deposition, and the interlayer temperature was controlled within a preset window during the deposition process.

[0032] S4 Path Planning and Parameter Setting: Layered slicing and processing path planning are performed based on the 3D model or the contour of the repair area. The laser power P is 2.5kW, the scanning speed v is 10mm / s, the powder feed rate F is 12g / min, the spot diameter is 0.8~3.0mm, the inter-pass overlap rate is 30%~60%, and the layer thickness is 0.2~0.8mm. The deposition path adopts a short-pass partitioning combined with staggered scanning to carry out layer-by-layer deposition.

[0033] S5 Layer-by-Layer Deposition: Coaxial powder feeding deposition is performed under a protective atmosphere, using a path strategy of short-channel partitioning combined with staggered scanning for layer-by-layer deposition; if necessary, the power, speed, or powder feed rate can be finely adjusted according to the stable state of the molten pool.

[0034] S6 interface partitioning: such as Figure 3 and Figure 4As shown, in the initial stage of laser irradiation, the Ta shell preferentially melts and establishes a Ta-enriched region near the interface. Subsequently, the Ta-W core gradually participates in melting and mass transfer under the influence of heat input and diffusion, allowing W elements to enter the upper molten pool region in a delayed manner, which is conducive to the formation of a Ta enrichment reaction suppression transition zone and a Ti-Ta mixed transition zone. Near the overall interface between the deposit and the Ti60 titanium alloy matrix, a multi-level interface transition structure can be formed, consisting of a Ta10W deposit layer, a Ta enrichment reaction suppression transition zone, a Ti-Ta mixed transition zone, a heat-affected zone, and a Ti60 titanium alloy matrix layer. During subsequent layer-by-layer deposition, due to the local remelting and re-fusion of the underlying material by the new deposit layer, the Ta10W deposit layer and the Ta enrichment reaction suppression transition zone below it can locally repeat between layers; however, the Ti-Ta mixed transition zone, the heat-affected zone, and the Ti60 titanium alloy matrix layer are mainly formed in the overall interface region between the deposit and the matrix. The multi-level structure does not require the boundaries of each layer to be absolutely sharp, but rather refers to a continuous partitioning in terms of compositional distribution, relative function, and transition characteristics.

[0035] S7 Post-processing and Dimensional Finishing: After deposition, stress-relief annealing, local heat treatment, and / or machining can be performed according to the component's usage requirements to achieve the target dimensional accuracy and surface quality. After deposition, the deposited area undergoes stress-relief annealing, local heat treatment, and machining to achieve the target dimensional accuracy and surface quality.

[0036] This invention can be used to construct a multi-level thermal structural material consisting of a titanium alloy load-bearing matrix, an interface transition layer, and a tantalum-tungsten alloy high-temperature functional layer, for local strengthening, surface additive manufacturing, or service damage repair of high-temperature load-bearing components.

[0037] The above description is merely a preferred embodiment of the present invention. Any equivalent substitutions or conventional adjustments made by those skilled in the art to the core alloy composition, shell thickness, powder particle size, scanning path, preheating and interlayer temperature control methods, etc., without departing from the concept of the present invention, should fall within the protection scope of the present invention.

Claims

1. A laser-directed energy deposition method for manufacturing a Ti60 / tantalum-tungsten alloy multi-level thermal structure material, characterized in that, Includes the following steps: S1. Grinding, roughening and cleaning the surface of the Ti60 titanium alloy substrate, and determining the area to be manufactured or repaired. S2, prepare Ta10W@Ta core-shell engineering powder as powder feeding material, wherein Ta10W alloy particles are the core and Ta is the outer shell layer. The Ta shell layer is formed on the surface of Ta10W alloy particles by ball milling, adhesion, diffusion and sintering. S3, the Ta shell is a continuous coating layer or a semi-continuous coating layer, the shell thickness is 0.2 to 3 μm, the particle size D50 of the Ta10W core powder is 45 μm, and the particle size D50 of the Ta shell powder is 5 μm; S4. Using laser-directed energy deposition (EDD) technology, the Ta10W@Ta core-shell engineering powder is delivered to the surface or joint area of ​​the Ti60 titanium alloy substrate under Ar protective atmosphere and substrate preheating conditions, and layer-by-layer deposition is carried out. The laser power is 2.5kW, the scanning speed is 10mm / s, the powder feed rate is 12g / min, and the substrate preheating temperature is 350℃. S5, in the early stage of deposition, the Ta outer shell layer preferentially participates in melting and forms a Ta-enriched region near the interface between the deposit and the Ti60 titanium alloy matrix. Subsequently, the Ta10W core gradually participates in melting and mass transfer, thus forming a multi-level interface transition structure near the overall interface, including a tantalum-tungsten alloy deposit layer, a Ta enrichment reaction inhibition transition zone, a Ti-Ta mixed transition zone, and a heat-affected zone. S6. After deposition is completed, the deposition area is subjected to heat treatment, machining or surface finishing to obtain the multi-level thermal structure material.

2. The manufacturing method according to claim 1, characterized in that: The Ta shell is coated on the outer surface of the Ta10W core powder. The Ta shell is a continuous coating layer or a semi-continuous coating layer, and the shell thickness is 0.2 to 3 μm.

3. The manufacturing method according to claim 1, characterized in that: The core powder of Ta10W has a particle size D50 of 45 μm, and the shell powder of Ta has a particle size D50 of 5 μm.

4. The manufacturing method according to claim 1, characterized in that: In the laser-directed energy deposition process, the spot diameter is 0.8–3.0 mm, the inter-channel overlap rate is 30%–60%, and the layer thickness is 0.2–0.8 mm.

5. The manufacturing method according to claim 1, characterized in that: The protective gas is Ar, and the substrate preheating temperature is 350°C.

6. The manufacturing method according to claim 1, characterized in that: The deposition path employs a short-track partitioning combined with staggered scanning to perform layer-by-layer deposition.

7. A Ta10W@Ta core-shell engineering powder for use in the manufacturing method according to any one of claims 1 to 6, characterized in that: Using Ta10W alloy particles as the core and Ta as the outer shell, the Ta shell is formed on the surface of the Ta10W alloy particles by ball milling, adhesion, diffusion, and sintering. The Ta shell is a continuous or semi-continuous coating layer with a thickness of 0.2–3 μm. The particle size D50 of the Ta10W core powder is 45 μm, and the particle size D50 of the Ta shell powder is 5 μm.

8. A Ti60 / tantalum-tungsten alloy multi-level thermal structure material, characterized in that: The material comprises, in sequence, a tantalum-tungsten alloy deposition layer, a Ta enrichment reaction suppression transition zone, a Ti-Ta mixed transition zone, a heat-affected zone, and a Ti60 titanium alloy matrix layer near the overall interface between the deposit and the Ti60 titanium alloy matrix; wherein, the tantalum-tungsten alloy deposition layer is formed by Ta10W deposition, the Ta enrichment reaction suppression transition zone is located between the tantalum-tungsten alloy deposition layer and the Ti-Ta mixed transition zone, and the Ti-Ta mixed transition zone is located between the Ta enrichment reaction suppression transition zone and the heat-affected zone.

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