Assembly of components made of different materials

Abstract

The invention relates to an assembly comprising a first component and a second component made respectively of a first and second material, the first material and the second material having respectively a first coefficient of thermal expansion and a second coefficient of thermal expansion different from the first coefficient of thermal expansion, the first component and the second component being assembled along a longitudinal direction by means of a third component so as to create a first transition zone and a second transition zone between the components, said third component being made of a third material having a third coefficient of thermal expansion different from that of the first and second materials,The first and second transition zones exhibit, respectively, a mass ratio between the first material and the third material, and between the second material and the third material, which varies along the longitudinal and / or lateral direction. (Abstract figure: Fig. 1)

Description

Title of the invention: Assembly of components made of different materials

[0001] The present invention relates to an assembly of at least two components, and more particularly to an assembly of at least two components composed of different materials.

[0002] The assembly of two components made of different materials, for example, two metals, is known from the prior art. These complex assemblies are used in the manufacture of heat exchanger piping and / or for connecting cold box piping with stainless steel pipes used in ASUs (Air Separation Units). In these ASUs, a connection of pressurized elements must be ensured, for example, between the fluid inlet or outlet piping of aluminum heat exchangers and stainless steel piping, such as a piping in a treatment column of an ASU. These complex, bimetallic assemblies, also called mixed joints, provide certain thermomechanical functions, for example, a safety function such as sealing.Such assemblies can also, for example, ensure that the component can withstand significant pressure levels.

[0003] Document EP3141632A1 discloses a method for joining different materials that cannot be directly welded together, in which a sprayed layer is created by thermal spraying, in particular by cold gas spraying. This method allows a cohesive bond to be formed between the two materials. This method does not allow for the creation of assemblies resistant to high pressure levels. Furthermore, this method is complex to implement.

[0004] US patent 6886629B2 discloses a method for joining different materials that cannot be directly welded together, in which an intermediate piece is welded on one side to a first component and on the other side to another component. More specifically, this intermediate piece can be joined by an explosion plating process. This method uses an intermediate piece that may require a complex geometry, thus necessitating additional manufacturing steps that are costly and complex to implement.

[0005] Other methods for producing such assemblies are also known from the prior art. One solution, for example, is two-material shrink fitting between an aluminum component and a stainless steel component. Shrink fitting is the assembly by press-fitting an outer part called a "shrink fitting" and a The inner part is called a "shrink-fitted" part. Shrink fitting can be performed hot or cold, depending on the desired joint. Hot shrink fitting provides excellent mechanical strength. The inner or outer part is heated, for example, by induction, heat treatment in a furnace, or with a gas. The heated part expands and easily bonds with the other part. Once cooled, the resulting assembly ensures excellent mechanical strength. The shrink-fitting process eliminates the need for third-party components such as adhesives, rivets, or flanges. However, this assembly process requires very precise temperature control, making it complex to manage. Furthermore, shrink fitting necessitates the production of components with precise dimensional tolerances, which is costly and complex to manufacture. In addition, shrink fitting does not allow for the assembly of components with more complex shapes.

[0006] As explained, these complex assemblies must guarantee the mechanical, thermal, and functional performance of the assemblies or sub-assemblies present in the ASUs. However, most of the prior art processes mentioned do not guarantee this performance. Furthermore, these processes are often limited to parts of revolution, notably to limit costs. Moreover, these prior art manufacturing methods are limited to a single operating temperature range for a given assembly.

[0007] The present invention aims to effectively remedy these drawbacks by proposing an assembly of at least two components made of different materials with more complex geometries, adapted mechanical and thermal performance, and developed from manufacturing operations that are less expensive, fewer in number and simpler to implement.

[0008] The invention then relates to an assembly comprising a first component made of a first material and a second component made of a second material different from the first material, said first material and said second material having respectively a first coefficient of thermal expansion and a second coefficient of thermal expansion different from the first coefficient of thermal expansion, said first component and said second component being assembled one on top of the other in a longitudinal direction by means of a third component located between said first component and said second component so as to produce a first transition zone between said third component and said first component and a second transition zone between said third component and said second component,characterized in that said third component is made of a third material having a third coefficient of thermal expansion, said third coefficient of thermal expansion being different from the first coefficient of thermal expansion and said third coefficient of , thermal expansion being different from the second coefficient of thermal expansion and in that said first transition zone has a mass ratio between the first material and the third material varying along said longitudinal direction and / or along a lateral direction which is orthogonal to said longitudinal direction and said second transition zone has a mass ratio between the second material and the third material varying along the longitudinal direction and / or along said lateral direction.

[0009] Depending on the case, the invention may include one or more of the features set forth below.

[0010] Said first transition zone and / or said second transition zone comprise respectively a first material gradient and / or a second material gradient extending along said longitudinal direction, said first material gradient comprising a mass ratio between the first material and the third material varying along the longitudinal direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably again between 2% and 3%, over a first length measured along said longitudinal direction of 10 to 100 microns, said second material gradient comprising a mass ratio between the second material and the third material varying along the longitudinal direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably again between 2% and 3%, over a second length measured along said longitudinal direction of 10 to 100 microns.

[0011] Said first transition zone and / or said second transition zone comprise respectively a third material gradient and / or a fourth material gradient extending along said lateral direction, said third material gradient comprising a mass ratio between the first material and the third material varying along said lateral direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably again between 2% and 3%, over a third length measured along said lateral direction of 200 to 400 microns, said fourth material gradient comprising a mass ratio between the second material and the third material varying along said lateral direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably again between 2% and 3%, over a fourth length measured along said lateral direction of 200 to 400 microns.

[0012] Said third component includes at least one protrusion configured to protrude into said first component and / or said second component.

[0013] Said second component includes at least one protrusion configured to protrude into said third component.

[0014] The first material is an aluminum alloy and the second material is stainless steel.

[0015] The third material is copper or a copper alloy, for example a CuCrZr type copper alloy or a nickel-based alloy, for example Ni718 type.

[0016] The assembly is carried out using an additive manufacturing process, preferably using a laser powder bed fusion process.

[0017] The invention also relates to a fluid pipe fitting intended to connect a first fluid pipe and a second fluid pipe, the fitting comprising at least one assembly according to the invention, the first component being configured to be connected to said first pipe and the second component being configured to be connected to said second pipe.

[0018] The invention also relates to an air separation installation comprising at least a first pipe and a second pipe, the first pipe and the second pipe being connected by a fitting according to the invention, said first pipe comprising said first material and said second pipe comprising said second material.

[0019] The invention also relates to a method for manufacturing an assembly between a first component and a second component extending along a longitudinal direction A, by means of an additive manufacturing process, said first component being made of a first material and said second component being made of a second material different from said first material, said first material and said second material having respectively a first coefficient of thermal expansion and a second coefficient of thermal expansion different from the first coefficient of thermal expansion, said first component and said second component being assembled to each other by means of a third component made of a third material, said manufacturing process comprising the following steps:

[0020] a) provide a first powder comprising particles of said first material,

[0021] b) provide a second powder comprising particles of said second material,

[0022] c) provide a third powder comprising particles of said third material,

[0023] d) deposit a layer of said first or second powder onto a solid substrate or on an underlying layer of said first or second powder,

[0024] e) locally melt the layer of powder deposited by scanning with a laser beam, so as to form a molten bath,

[0025] f) cool the molten bath so as to solidify it,

[0026] repeat steps d) to f), until said first component or said second component is formed,

[0027] said process comprising the following additional steps:

[0028] g) deposit a layer comprising said third powder and said first or second powder on an underlying layer,

[0029] h) locally melt the layer of powder deposited in step g) by scanning with a laser beam, so as to form a molten bath,

[0030] i) cool the molten bath so as to solidify it,

[0031] repeat steps g) to i) so that a first transition zone between said third component and said first component, or a second transition zone between said third component and said second component is formed, said first transition zone having a mass ratio between the first material and the third material varying along said longitudinal direction and / or along a lateral direction which is orthogonal to the longitudinal direction and said second transition zone having a mass ratio between the second material and the third material varying along the longitudinal direction and / or along the lateral direction,

[0032] j) deposit a layer of said third powder on an underlying layer.

[0033] k) locally melt the layer of powder deposited in step j) by scanning with a laser beam, so as to form a molten bath,

[0034] 1) cool the molten bath so as to solidify it,

[0035] repeat steps j) to 1) so that said third component is formed,

[0036] repeat steps d) to f), until said first component or said second component is formed,

[0037] said third material having a third coefficient of thermal expansion, said third coefficient of thermal expansion being different from the first coefficient of thermal expansion and said third coefficient of thermal expansion being different from the second coefficient of thermal expansion.

[0038] Depending on the case, the invention may include one or more of the features set forth below.

[0039] During said steps g) to i) a first material gradient or a second material gradient is formed by the deposition of said third powder and said first powder along the longitudinal direction, said first material gradient comprising a mass ratio between the first material and the third material varying along the longitudinal direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably again between 2% and 3%, over a first length of 10 to 100 microns measured along the longitudinal direction, the second material gradient comprising a mass ratio between the second material and the third material varying along the longitudinal direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably again between 2% and 3%, over a second length of 10 to 100 microns measured along the longitudinal direction.

[0040] During said steps g) to i) a third material gradient or a fourth material gradient is formed by the deposition of said third powder and said first powder along said lateral direction, said third material gradient comprising a mass ratio between the first material and the third material varying along said lateral direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably again between 2% and 3%, over a third length of 200 to 400 microns measured along said lateral direction, said fourth gradient comprising a mass ratio between the second material and the third material varying along said lateral direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably again between 2% and 3%, over a fourth length of 200 to 400 microns measured along said lateral direction.

[0041] The invention will be better understood upon reading the following description and examining the accompanying figures. These figures are given only to illustrate, but in no way limit, the invention.

[0042] [Fig. 1] is a schematic representation of the assembly of two components according to an embodiment of the invention;

[0043] [Fig.2] is a partial schematic representation of the assembly interface of two components according to an embodiment of the invention;

[0044] With reference to [Fig. 1], the invention relates to an assembly between a first component 1 and a second component 2. These two components extend along a longitudinal direction A. The first component 1 is made of a first material and the second component 2 is made of a second material different from the first material. Said first and second materials have, respectively, a first coefficient of thermal expansion and a second coefficient of thermal expansion different from the first coefficient of thermal expansion. The two components are joined to each other by means of a third component 3. This third component 3 is therefore located between said first component 1 and said second component 2. A first transition zone 13 is formed between said third component 3 and said first component 1. A second transition zone 23 is formed between said third component 3 and said second component 2.It is in these transition zones that the assembly is effective. Indeed, these transition zones allow the definition of the desired mechanical and thermal characteristics of the assembly. The third component 3 is made of a third material having a third coefficient of thermal expansion, said third coefficient of thermal expansion being different from the first coefficient of thermal expansion, and said third coefficient of thermal expansion being different from the second coefficient of thermal expansion. Thus, for example, when the coefficient of expansion of the third material is greater than the coefficient of expansion of the first material, the third component is in compression in the first transition zone. The first transition zone 13 has a mass ratio between the . The first material and the third material vary along the longitudinal direction A and / or along a lateral direction orthogonal to the longitudinal direction A. The second transition zone 23 has a mass ratio between the second and third materials that varies along the longitudinal direction A and / or along the lateral direction. The first transition zone 13 and the second transition zone 23 are defined so that the assembly withstands the mechanical and thermal stresses experienced in use. Therefore, the assembly of the invention can have diverse and complex geometries and exhibit mechanical and thermal performance adapted to the intended use.

[0045] In one embodiment, the first material is an aluminum alloy, the second material is stainless steel. In another embodiment, the third material is copper or a copper alloy, for example a CuCrZr type copper alloy or a nickel-based alloy, for example Ni718 type.

[0046] In one embodiment, the first transition zone 13 comprises a first material gradient extending along the longitudinal direction A and / or the second transition zone 23 comprises a second material gradient extending along the longitudinal direction A. The first material gradient comprises a mass ratio between the first material and the third material varying along the longitudinal direction A from 0.05% to 10%, preferably from 0.05% to 5%, and more preferably from 2% to 3%, over a first length measured along the longitudinal direction A from 10 to 100 microns. The second material gradient comprises a mass ratio between the second material and the third material varying along the longitudinal direction A from 0.05% to 10%, preferably from 0.05% to 5%, and more preferably from 2% to 3%, over a second length measured along the longitudinal direction A from 10 to 100 microns.Thus, the resulting assembly withstands the mechanical and thermal stresses encountered in use. It exhibits mechanical characteristics that allow it to withstand high stresses, such as high pressure levels, for example, 150 bar. Furthermore, the assembly is no longer limited to a cylindrical shape. It can therefore have a more complex form. For example, the assembly of the invention may have a component 1, a component 2, and a component 3 with diverse and complex geometries, and offer mechanical and thermal performance adapted to the intended use.

[0047] In one embodiment, the first transition zone 13 comprises a third material gradient extending in the laterally direction and / or the second transition zone 23 comprises a fourth material gradient extending in the laterally direction. The third material gradient comprises a mass ratio between the first material and the third material varying in the lateral direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably even more between 2% and 3%, over a third length measured laterally from 200 to 400 microns. The fourth material gradient comprises a mass ratio between the second and third materials varying laterally between 0.05% and 10%, preferably between 0.05% and 5%, and preferably again between 2% and 3%, over a fourth length along the lateral direction from 200 to 400 microns. Thus, the resulting assembly resists the mechanical and thermal stresses encountered in use. The assembly exhibits mechanical characteristics that allow it to withstand high stresses, for example, high pressure levels, such as 150 bar. Furthermore, the assembly is no longer limited to a cylindrical shape. It can therefore have a more complex form.The assembly of the invention may, for example, have a component 1, a component 2 and a component 3 having diverse and complex geometries and exhibiting suitable mechanical and thermal performance.

[0048] In one embodiment, the first component 1 and the second component 2 have a minimum length of 20 mm. Thus, the first and second components can be welded onto conventional parts, for example, a pipe of an ASU. This minimum length prevents damage to the transition zones 13, 23 described with the third component during welding. This minimum length also ensures that the mechanical integrity of the third component itself is preserved during welding. In one embodiment, the first component 1 and the second component 2 have a circular cross-section and a diameter between 10 mm and 1200 mm. In another embodiment, the first and second components have a circular cross-section and a maximum diameter of 50 mm. In another embodiment, the thickness of the first and second components, both of which have a cylindrical cross-section, is between 10 and 1200 mm.

[0049] With reference to [Fig. 2], in one embodiment, the third component 3 includes at least one protrusion configured to project into the first component 1 and / or the second component 2. The protrusion is located in the transition zone 13, 23. In one embodiment, the second component 2 includes at least one protrusion configured to project into said third component 3. The protrusion is located in the transition zone 23. Thus, thanks to the at least one protrusion, the first transition zone 13 or the second transition zone 23 is increased, that is to say, the contact surface between the first component 1 and the third component 3 and / or the contact surface between the second component 1 and the third component 3 is increased. Therefore, the assembly is even more resistant to the stresses it undergoes.The assembly of the invention may, for example, have a component 1, a component 2 and a component 3 with diverse and complex geometries and with adapted mechanical and thermal performance. The contact surface between the second component 2 and the third component 3 is increased. This makes the assembly even more resistant to stresses such as bending, torsion, or shear. The protrusion allows for better distribution of mechanical forces in the transition zone 13, 23. This protrusion can, for example, be in the shape of a parallelepiped or a cylinder. It can also be dovetailed, fir-tree shaped, or have a more complex form. In one embodiment, the protrusion comprises at least one branched protrusion. In another embodiment, the protrusion comprises a plurality of branched protrusions. This protrusion or branched protrusion extends in any direction, for example, along the longitudinal direction A or along the lateral direction.

[0050] The choice of materials is adapted according to the desired assembly and according to their coefficient of expansion. In one embodiment, and for an ambient temperature between 0 and 200°C, the third material has a coefficient of expansion of 14 to 18 x 10-6.K-1, preferably 17 x 10-6.K-1, said first material has a coefficient of expansion of 22 to 30 x 10-6.K-1, and said first material has a coefficient of expansion of 12 to 16 x 10-6.Kl, preferably 15 x 10-6.K-1.

[0051] In one embodiment, the third material has a coefficient of thermal expansion at least 1.5 times greater than that of the first material and a coefficient of thermal expansion at least 1.5 times less than that of the second material.

[0052] In one embodiment, the assembly is carried out using an additive manufacturing process, preferably using a laser powder bed fusion process.

[0053] The invention also relates to a fluid pipe fitting for connecting a first fluid pipe made of the first material and a second fluid pipe made of the second material. The fitting comprises at least one assembly of the invention. Thus, the first component of the assembly is configured to be connected to the first pipe and the second component is configured to be connected to the second pipe.

[0054] The invention also relates to an air separation installation comprising at least one first pipe comprising the first material and a second pipe comprising the second material, the first and second pipes being connected by a fitting according to the invention. The first pipe is, for example, the pipe of a heat exchanger, made of aluminum and the second pipe is, for example, the pipe of a distillation column, made of steel.

[0055] The invention also relates to an additive manufacturing process for an assembly between a first component 1 and a second component 2 extending along a longitudinal axis A, by means of an additive manufacturing process, said first component 1 being made of a first material and said second component 2 being made of a second material different from said first material, said first material and said second material having respectively a first coefficient of thermal expansion and a second coefficient of thermal expansion different from the first coefficient of thermal expansion, said first component 1 and said second component 2 being joined to each other by means of a third component 3 made of a third material. The third material has a third coefficient of thermal expansion.This third coefficient of thermal expansion differs from the first coefficient of thermal expansion, and this third coefficient of thermal expansion differs from the second coefficient of thermal expansion. It is this difference that allows the assembly of the invention to withstand significant mechanical and thermal stresses.

[0056] The manufacturing process comprises the following steps:

[0057] First, first, second and third powders comprising respectively particles of the first, second and third materials are supplied into an additive manufacturing machine in the respective steps a), b) and c).

[0058] Then, in step d), a layer of the first or second powder is deposited onto a solid substrate or onto an underlying layer of the first or second powder. The solid substrate is located within the build chamber of the additive manufacturing machine. The deposited layer is then locally melted by scanning a laser beam during step e), so as to form a molten pool. Then, in step f), this molten pool is cooled, either by means of a gas or naturally, i.e., without any specific means. The molten pool is then solidified. Steps d) to f) are then repeated. This repetition allows the layer-by-layer formation of the first component 1 or second component 2, depending on the powder deposited during step d).These steps are therefore repeated until the first and second components are formed and before the formation of a transition zone 13, 23 which materializes the junction, the assembly between the first component 1 or the second component 2 and the third component 3. .

[0059] In a step g), a layer of powder is deposited on the underlying layer. In this step g), this layer comprises the third powder and the first or second powder.

[0060] In step h), the powder layer deposited in step g) is locally melted by scanning with a laser beam, so as to form a molten bath. In step i), the molten bath is cooled in the same way as in step f). Steps g) to i) are then repeated. This repetition allows the layer-by-layer formation of a first transition zone 13 between the third component 3 and the first component 1, or of a second transition zone 23 between the third component 3 and the second component 2.

[0061] In one embodiment, during steps g) to i) a first material gradient or a second material gradient is formed by depositing powder of the third powder with the first or second powder along the longitudinal direction A. The first material gradient or the second material gradient comprises a mass ratio between the first material and the third material varying between 0.05% and 10%, preferably between 0.05% and 5%, preferably further between 2% and 3%, over a first length of 10 to 100 microns along the longitudinal direction A. The second material gradient comprises a mass ratio between the second material and the third material varying between 0.05% and 10%, preferably between 0.05% and 5%, preferably further between 2% and 3%, over a second length of 10 to 100 microns along the longitudinal direction A.

[0062] In this embodiment, during steps g) to i), a third or fourth material gradient is formed by depositing said third powder and said first or second powder in the lateral direction. The third material gradient comprises a mass ratio varying in the lateral direction from 0.05% to 10%, preferably from 0.05% to 5%, and more preferably from 2% to 3%, over a length of 10 to 100 microns in the lateral direction. The fourth material gradient comprises a mass ratio varying in the lateral direction from 0.05% to 10%, preferably from 0.05% to 5%, and more preferably from 2% to 3%, over a length of 10 to 100 microns in the lateral direction.

[0063] Then, in step j), a third powder is deposited on an underlying layer. In step k), the powder layer thus deposited in step j) is locally melted by scanning with a laser beam, so as to form a molten pool. In step 1), the molten pool is cooled in the same way as in step f). Steps k) to 1) are then repeated. This repetition allows the layer-by-layer formation of the third component 3.

[0064] Thus, the assembly of the first component 1 and the second component 2 is carried out using the same process. The assembly of the invention is therefore developed from manufacturing operations that are less expensive, fewer in number, and simpler to implement.

Claims

Demands

1. Assembly comprising a first component (1) made of a first material and a second component (2) made of a second material different from the first material, said first material and said second material having respectively a first coefficient of thermal expansion and a second coefficient of thermal expansion different from the first coefficient of thermal expansion, said first component (1) and said second component (2) being assembled one on top of the other along a longitudinal direction (A) by means of a third component (3) situated between said first component (1) and said second component (2) so as to produce a first transition zone (13) between said third component (3) and said first component (1) and a second transition zone (23) between said third component (3) and said second component (2),characterized in that said third component (3) is made of a third material having a third coefficient of thermal expansion, said third coefficient of thermal expansion being different from the first coefficient of thermal expansion and said third coefficient of thermal expansion being different from the second coefficient of thermal expansion, and in that said first transition zone (13) has a mass ratio between the first material and the third material that varies along said longitudinal direction (A) and / or along a lateral direction that is orthogonal to said longitudinal direction (A), and said second transition zone (23) has a mass ratio between the second material and the third material that varies along the longitudinal direction (A) and / or along said lateral direction.

2. An assembly according to claim 1, characterized in that said first transition zone (13) and / or said second transition zone (23) comprise respectively a first material gradient and / or a second material gradient extending along said longitudinal direction (A), said first material gradient comprising a mass ratio between the first material and the third material varying along the longitudinal direction (A) from 0.05% to 10%, preferably from 0.05% to 5%, preferably further from 2% to 3%, over a first length measured along said longitudinal direction (A) from 10 to 100 microns, said second material gradient comprising a mass ratio between the second material and the third material varying along the longitudinal direction (A) between 0.05% and 10%, preferably between 0.05% and 5%, preferably again between 2% and 3%, over a second length measured along said longitudinal direction (A) from 10 to 100 microns.

3. Assembly according to claim 1 or 2, characterized in that said first transition zone (13) and / or said second transition zone (23) respectively comprise a third material gradient and / or a fourth material gradient extending along said lateral direction, said third material gradient comprising a mass ratio between the first material and the third material varying along said lateral direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably further between 2% and 3%, over a third length measured along said lateral direction of 200 to 400 microns, said fourth material gradient comprising a mass ratio between the second material and the third material varying along said lateral direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably further between 2% and 3%, over a fourth length measured along said lateral direction of 200 to 400 microns.

4. Assembly according to any one of the preceding claims, characterized in that said third component (3) comprises at least one protrusion configured to protrude into said first component (1) and / or said second component (2).

5. Assembly according to any one of the preceding claims, characterized in that said second component (2) comprises at least one protrusion configured to protrude into said third component (3).

6. Assembly according to any one of the preceding claims, characterized in that the first material is an aluminum alloy and the second material is a stainless steel.

7. Assembly according to any one of the preceding claims, characterized in that the third material is copper or a copper alloy, for example a CuCrZr type copper alloy or a nickel-based alloy, for example of the Ni718 type.

8. Assembly according to any one of the preceding claims, characterized in that it is carried out by means of an additive manufacturing process, preferably by means of a laser powder bed fusion process.

9. Fluid pipe fitting for connecting a first fluid pipe and a second fluid pipe, the fitting being characterized in that it comprises at least one assembly according to any one of claims 1 to 8, the first component being configured to be connected to said first pipe and the second component being configured to be connected to said second pipe.

10. Air separation installation comprising at least a first pipe and a second pipe, the first pipe and the second pipe being connected by a fitting according to claim 9, said first pipe comprising said first material and said second pipe comprising said second material.

11. A method for manufacturing an assembly between a first component (1) and a second component (2) extending along a longitudinal direction A, by means of an additive manufacturing process, said first component (1) being made of a first material and said second component (2) being made of a second material different from said first material, said first material and said second material having respectively a first coefficient of thermal expansion and a second coefficient of thermal expansion different from the first coefficient of thermal expansion, said first component (1) and said second component (2) being joined to each other by means of a third component (3) made of a third material, said manufacturing process comprising the following steps: a) providing a first powder comprising particles of said first material,b) supply a second powder comprising particles of said second material, c) supply a third powder comprising particles of said third material, (d) deposit a layer of said first or second powder onto a solid substrate or onto an underlying layer of said first or second powder, e) locally melt the layer of powder deposited by scanning with a laser beam, so as to form a molten bath, f) cool the molten bath so as to solidify it, repeat steps d) to f), until said first component (1) or said second component (2) is formed, said process being characterized in that it comprises the following additional steps: (g) deposit a layer comprising said third powder and said first or second powder onto an underlying layer, (h) locally melt the powder layer deposited in step (g) by scanning with a laser beam, so as to form a molten bath, (i) cool the molten bath so as to solidify it, repeat steps (g) to (i) so that a first transition zone (13) between said third component (3) and said first component (1), or a second transition zone (23) between said third component (3) and said second component (2) is formed,said first transition zone (13) having a mass ratio between the first material and the third material varying along said longitudinal direction (A) and / or along a lateral direction orthogonal to the longitudinal direction (A) and said second transition zone (23) having a mass ratio between the second material and the third material varying along the longitudinal direction (A) and / or along the lateral direction, j) deposit a layer of said third powder on an underlying layer. (k) locally melt the layer of powder deposited in step (j) by scanning with a laser beam, so as to form a molten bath, (1) cool the molten bath so as to solidify it, repeat steps (j) to (1) so that said third component (3) is formed, deposit a layer of said first or second powder on said third component, repeat steps (d) to (f), until said first component (1) or said second component (2) is formed, said third material having a third coefficient of thermal expansion, said third coefficient of thermal expansion being different from the first coefficient of thermal expansion and said third coefficient of thermal expansion being different from the second coefficient of thermal expansion.

12. A method for manufacturing an assembly according to claim 11, characterized in that during said steps g) to i) a first material gradient or a second material gradient is formed by deposition of said third powder with said first or second powder along the longitudinal direction (A), said first material gradient comprising a mass ratio between the first material and the third material varying along the longitudinal direction (A) between 0.05% and 10%, preferably between 0.05% and 5%, preferably further between 2% and 3%, over a first length of 10 to 100 microns measured along the longitudinal direction (A), the second material gradient comprising a mass ratio between the second material and the third material varying along the longitudinal direction (A) between 0.05% and 10%, preferably between 0.0.5% and 5%, preferably still between 2% and 3%, over a second length of 10 to 100 microns measured along the longitudinal direction (A).

13. A method for manufacturing an assembly according to claim 11 or 12, characterized in that during said steps g) to i) a third material gradient or a fourth material gradient is formed by deposition of said third powder and said first or second powder along said lateral direction, said third material gradient comprising a mass ratio between the first material and the third material varying along said lateral direction between 0.05% and 10%, preferably between 0.05% and 5%, preferably further between 2% and 3%, over a third length of 200 to 400 microns measured along said lateral direction, said fourth gradient comprising a mass ratio between the second material and the third material varying along said lateral direction between 0.05% and 10%, preferably between 0.0.5% and 5%, preferably still between 2% and 3%, over a fourth length of 200 to 400 microns measured along said lateral direction.

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