Transient connection method of additive high-temperature alloy part and additive manufacturing high-temperature alloy component

Abstract

The invention provides a transient connection method of an additive high-temperature alloy part and an additive manufacturing high-temperature alloy part, and relates to the technical field of high-temperature alloy connection.The welding method comprises the following steps that a middle-layer welding flux is added to a to-be-welded area, and a to-be-welded part is obtained; wherein the to-be-welded area is formed by oppositely arranging a to-be-welded part of the first base metal and a to-be-welded part of the second base metal at an interval; wherein the first base material and the second base material are additive high-temperature alloy parts; carrying out transient liquid phase connection treatment on the to-be-welded part, so that the first base metal, the intermediate layer welding flux and the second base metal are connected together; wherein the intermediate layer solder comprises the following chemical components in percentage by weight: 11%-17% of Cr, 5%-9% of W, 1%-3.5% of B, 0.3%-3% of Hf, 0.3%-3% of Zr and the balance of Ni. According to the method, the separately printed additive manufacturing high-temperature alloy parts are connected through the transient liquid phase connection process to obtain a complete component with a complex structure and high surface quality, so that the problem that additive manufacturing is poor in inner cavity and surface smoothness is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature alloy connection, and in particular relates to a transient liquid phase connection method and a joint for additive high-temperature alloys. Background Art

[0002] Additive manufacturing of high-temperature alloys is a process of printing high-temperature alloys by spreading or feeding high-temperature alloy powders of appropriate particle size, thereby achieving a shorter manufacturing cycle, lower manufacturing costs, and less raw material consumption than traditional casting and forging technology. It has been widely used in the production of various parts of aircraft engines and gas turbines.

[0003] However, due to the limitations of existing technologies, whether it is the powder laying process or the powder feeding process, the smoothness of the inner cavity and surface of the high-temperature alloy components is far behind that of the traditional investment casting process. In addition, when manufacturing the inner cavity structure of parts with high dimensional accuracy requirements, support materials must be used to ensure the inner cavity dimensional accuracy. If the inner cavity structure is complex, the support material cannot be removed after manufacturing. Summary of the invention

[0004] Therefore, the present invention provides a transient liquid phase connection method and joint for additively manufactured high-temperature alloys, which can solve the problem of poor smoothness of the inner cavity and outer surface of additively manufactured high-temperature alloy components in the prior art.

[0005] In order to solve the above problems, the present invention provides a transient connection method of additive high-temperature alloy parts, and the welding method comprises the following steps:

[0006] Step 1): adding an intermediate layer of solder to the area to be welded to obtain a part to be welded; wherein the area to be welded is formed by a portion to be welded of the first parent material and a portion to be welded of the second parent material being arranged relatively spaced apart;

[0007] Wherein, the first parent material and the second parent material are both additive high temperature alloy parts;

[0008] Step 2): performing transient liquid phase connection treatment on the parts to be welded, so that the first base material, the intermediate layer solder, and the second base material are connected together;

[0009] Wherein, the chemical composition of the intermediate layer solder is, by weight percentage, Cr11%-17%, W5%-9%, B1%-3.5%, Hf0.3%-3%, Zr0.3%-3%, and Ni balance.

[0010] Further, the intermediate layer solder is a foil strip solder;

[0011] Preferably, the thickness of the foil strip solder is 0.02-0.06 mm.

[0012] Further, the step of adding an intermediate layer of solder to the area to be welded includes: placing the foil strip solder inside the area to be welded; preferably, it also includes: spot welding the foil strip solder in a set area; wherein the set area is an area within 2 mm from the area to be welded; further preferably, the amount of foil strip solder in the set area is greater than or equal to the amount of foil strip solder inside the area to be welded; and / or

[0013] The foil strip solder is prepared by a melt rapid quenching process; preferably, the parameters of the melt rapid quenching process are: melting temperature of 1390-1590°C; spraying temperature of 1410-1510°C; roller surface linear speed of 20-35m / s; and the distance between the nozzle and the roller surface of 0.2-0.4mm.

[0014] Furthermore, the intermediate layer solder is powdered solder; preferably, the particle size of the powdered solder is less than or equal to 100 μm.

[0015] Further, the step of adding an intermediate layer of solder to the area to be soldered includes: mixing the powdered solder with an adhesive to obtain a solder paste; and then placing the solder paste in a set area; wherein the set area is an area within 2 mm from the area to be soldered; preferably, in the solder paste, the mass ratio of the powdered solder is 87%-93%; the volume of the solder paste in the set area is not less than 3 times the volume of the area to be soldered; and / or

[0016] The powdered solder is prepared by a gas atomization process; preferably, the parameters of the gas atomization process are: melting temperature is 1390-1590°C; powder spraying temperature is 1410-1570°C; atomizing gas is argon; and atomizing pressure is 4-10MPa.

[0017] Further, the chemical composition of the first parent material is, by weight percentage: Cr 6%-16%, Co 6%-10%, W 6%-11%, Mo 0.5%-3%, Al 3%-6%, Ti 0.5%-3.6%, Ta 1%-6%, Nb 0-1%, C ≤ 0.2%, B ≤ 0.1%, Hf ≤ 2%, Ni balance; and / or

[0018] The chemical composition of the second parent material is, by weight percentage, Cr 6%-16%, Co 6%-10%, W 6%-11%, Mo 0.5%-3%, Al 3%-6%, Ti 0.5%-3.6%, Ta 1%-6%, Nb 0-1%, C ≤ 0.2%, B ≤ 0.1%, Hf ≤ 2%, Ni balance; and / or

[0019] The additively manufactured high-temperature alloy part is prepared by a laser selective melting process or a laser melting deposition process.

[0020] Furthermore, in the step 1), the surface roughness of the to-be-welded portion of the first base material is Ra0.2-Ra0.8; and / or

[0021] The surface roughness of the to-be-welded portion of the second base material is Ra0.2-Ra0.8; and / or

[0022] The gap to be welded is less than or equal to 0.08 mm; and / or

[0023] After the step of adding an intermediate layer of solder to the area to be welded, the method further includes: coating a flow blocker on the non-welded parts of the first and second base materials; preferably, the flow blocker is not in contact with the intermediate layer of solder, and the distance between the coating position of the flow blocker and the intermediate layer of solder is less than or equal to 2 mm.

[0024] Furthermore, in the step 2), a vacuum heat treatment furnace or a vacuum brazing furnace is used to perform transient liquid phase connection treatment; preferably, the atmosphere in the furnace is vacuum or argon; and / or

[0025] Before the step of transient liquid phase connection treatment, the method further includes: drying the parts to be connected; the drying temperature is 90-120° C.; the drying time is 40-60 minutes; and / or

[0026] After the step of transient liquid phase connection treatment, the method further includes: cooling treatment; preferably, the cooling treatment adopts a furnace cooling method.

[0027] Further, the transient liquid phase connection process includes annealing and connection processes performed in sequence; preferably, the temperature of the annealing process is 1020-1040°C; the time of the annealing process is 60-240 minutes; preferably, the temperature of the connection process is 1120-1200°C; the time of the connection process is 100-360 minutes. On the other hand, the present invention provides an additively manufactured high-temperature alloy component, wherein the additively manufactured high-temperature alloy component is a welded part obtained by any of the welding methods described above;

[0028] No non-isothermal solidification structure is observed at the weld of the additively manufactured high-temperature alloy component; the microstructure at the weld includes a γ phase and a γ′ phase; the γ′ phase is uniformly dispersed at the weld; the γ′ phase is nearly cubic, and the volume fraction of the γ′ phase is 45-55%;

[0029] Preferably, the shear strength of the additively manufactured high-temperature alloy component at 980° C. is greater than or equal to 320 MPa.

[0030] The instantaneous connection method of an additive high-temperature alloy part and the additively manufactured high-temperature alloy component provided by the present invention have the following beneficial effects:

[0031] 1. The present invention provides a transient connection method for additive high-temperature alloy parts, comprising the following steps: adding an intermediate layer of solder to a region to be welded to obtain a member to be welded; wherein the region to be welded is formed by a relative spacing between a portion to be welded of a first parent material and a portion to be welded of a second parent material; wherein the first parent material and the second parent material are both additive high-temperature alloy parts; performing transient liquid phase connection treatment on the member to be welded to connect the first parent material, the intermediate layer of solder, and the second parent material together; it should be noted that by splitting a component into multiple parts and obtaining multiple parts through additive manufacturing, the original inner cavity can be exposed to become an outer surface, and then the inner cavity can be machined into a desired size and desired finish by machining. Based on the above method, the additively manufactured high-temperature alloy parts printed separately are connected through a transient liquid phase connection process to obtain a complete component with a complex structure and high surface quality, thereby solving the problem of poor inner cavity and surface finish in additive manufacturing; at the same time, no support material is required to ensure the dimensional accuracy of the inner cavity, so there is no need to remove the support material, thereby reducing the process difficulty, improving the manufacturing qualification rate, and reducing the production cost.

[0032] 2. Furthermore, in the middle layer solder, adding Cr element can improve the oxidation resistance and corrosion resistance of the weld, and play a role in solid solution strengthening; adding W element can enhance the solid solution strengthening effect; in addition, in addition to B element, adding auxiliary melting reduction elements Hf and Zr can not only reduce the melting point of the solder, but also play a role in solid solution strengthening of the weld matrix, thereby improving the strength of the joint, and the introduction of Hf and Zr can reduce the addition of B element, thereby avoiding local stress concentration caused by excessive B element enrichment, and reducing the cracking sensitivity of strain aging cracks and ductile loss plastic cracks of the components after welding; the addition of the above alloying elements can make the middle layer solder have excellent connection processability; at the same time, the weld matrix maintains a single-phase γ solid solution with a large mismatch and low stacking fault energy, and avoids the precipitation of other second phases except the γ′ precipitation strengthening phase, which is beneficial to ensure the mechanical properties of the joint after welding.

[0033] 3. Furthermore, through annealing treatment, the original γ′ phase of the first parent material and the second parent material is first dissolved back to release the internal stress, and then through connection treatment, sufficient element mutual diffusion is achieved to obtain a high-performance dense joint, and the γ′ precipitation strengthening phase is re-precipitated in the weld and the parent material during the cooling process; wherein, during the connection process, the weld and the parent material are both in a low stress state, and the connection process is completed under a low strength and high plasticity state, avoiding the influence of stress on the connection process, and the connected joint regains a high-strength structure.

[0034] 4. On the other hand, the present invention provides an additively manufactured high-temperature alloy component, which is a welded part obtained by any of the welding methods described above; no non-isothermal solidification structure is observed at the weld of the additively manufactured high-temperature alloy component; and the shear strength at 980°C is greater than or equal to 320 MPa; the additively manufactured high-temperature alloy component obtained by the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0036] Figure 1 is a microscopic image of an additively manufactured high-temperature alloy component obtained in Example 1 of the present invention;

[0037] Figure 2 is a microscopic image of an additively manufactured high-temperature alloy component obtained in Comparative Example 1 of the present invention;

[0038] Figure 3 This is a microscopic image of the additively manufactured high-temperature alloy component obtained in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0039] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0040] The present invention provides a transient connection method for additive high-temperature alloy parts, and the welding method comprises the following steps:

[0041] Step 1): adding an intermediate layer of solder to the area to be welded, and then coating a flow barrier on the non-to-be-welded portion of the first parent material and the second parent material to obtain a part to be welded; wherein the area to be welded is formed by the relative spacing between the to-be-welded portion of the first parent material and the to-be-welded portion of the second parent material;

[0042] The step is specifically as follows: processing the to-be-welded portion of the first parent material and the to-be-welded portion of the second parent material until the surface roughness is Ra0.2-Ra0.8; cleaning the to-be-welded portion with anhydrous ethanol or acetone; then adding an intermediate layer of solder in the to-be-welded area, and coating a flow barrier on the non-to-be-welded portion of the first parent material and the second parent material to obtain the to-be-welded part; wherein the surface roughness of the to-be-welded portion of the first parent material and the second parent material is limited to Ra0.2-Ra0.8 to avoid the surface being too rough or too smooth to affect the flow and gap-filling ability of the solder.

[0043] The current blocker does not contact the middle layer solder, and the distance between the coating position of the current blocker and the middle layer solder is less than or equal to 2 mm; the gap to be welded is less than or equal to 0.08 mm; the first parent material and the second parent material are both additive high-temperature alloy parts prepared by laser selective melting process or laser melting deposition process; in terms of weight percentage, the chemical compositions of the first parent material and the second parent material are: Cr6%-16%, Co6%-10%, W6%-11%, Mo0.5%-3%, Al3%-6%, Ti0.5% -3.6%, Ta1%-6%, Nb0~1%, C≤0.2%, B≤0.1%, Hf≤2%, Ni balance; wherein, a flow blocker is used to prevent the solder from flowing to the non-to-be-welded part; the flow blocker may be an alumina-based flow blocker or a chromium oxide-based flow blocker. The present application adopts an alumina-based flow blocker for easy removal; if the gap to be welded is too large, it is difficult to achieve complete isothermal solidification during the annealing and insulation process, thereby forming a non-equilibrium solidification zone in the weld, and a low melting point eutectic structure will exist in this area, thereby affecting the mechanical properties of the joint after welding.

[0044] Calculated by weight percentage, the chemical composition of the intermediate layer solder is: Cr11%-17%, W5%-9%, B1%-3.5%, Hf0.3%-3%, Zr0.3%-3%, and Ni balance.

[0045] Step 2): Perform transient liquid phase connection treatment on the workpiece to be welded, so that the first base material, the middle layer solder and the second base material are connected together.

[0046] The specific steps are as follows: after the parts to be welded are placed in a drying oven for drying, they are placed in a vacuum heat treatment furnace or a vacuum brazing furnace for annealing and connection treatment in sequence, and then cooled with the furnace; wherein the drying temperature is 90-120°C; the drying time is 40-60min; the annealing temperature is 1020-1040°C; the annealing time is 60-240min; the connection temperature is 1120-1200°C; the connection time is 100-360min; the furnace atmosphere is vacuum or argon; wherein, during the furnace cooling treatment, the temperature is lowered to below 80°C and the parts are taken out of the furnace. The cooling rate of furnace cooling is slow, which can avoid cracking of the joint or the base material; the purpose of taking out of the furnace below 80°C is to avoid oxidation of parts and furnace chamber caused by excessively high temperature.

[0047] In some embodiments, the middle layer solder is a foil strip solder; preferably, the thickness of the foil strip solder is 0.02-0.06 mm; at this time, the step of adding the middle layer solder to the area to be welded includes: placing the foil strip solder inside the area to be welded, and spot welding the foil strip solder in a set area; wherein the set area is an area within 2 mm from the area to be welded; the amount of foil strip solder in the set area is greater than or equal to the amount of foil strip solder inside the area to be welded; wherein the number of layers of foil strip solder depends on the gap to be welded and the thickness of the foil strip.

[0048] The above-mentioned foil strip solder is prepared by melt rapid quenching process; the parameters of the melt rapid quenching process are: melting temperature of 1390-1590°C; spraying temperature of 1410-1510°C; roller surface linear speed of 20-35m / s; and the distance between the nozzle and the roller surface of 0.2-0.4mm.

[0049] In some embodiments, the intermediate layer solder is powdered solder; the particle size of the powdered solder is less than or equal to 100 μm, which is convenient for subsequent mixing of the solder, placing it in a set area, and other operations; the step of adding the intermediate layer solder to the area to be welded includes: mixing the powdered solder with an adhesive to obtain a solder paste; then placing the solder paste in a set area; wherein the set area is an area within 2 mm from the area to be welded; in the solder paste, the mass ratio of the powdered solder is 87%-93%; the volume of the solder paste in the set area is not less than 3 times the volume of the area to be welded. wherein, the solder paste is placed in the set area to avoid excessive melting of the non-welding area; the adhesive can be a water-based adhesive or an oily adhesive. Through the above-mentioned drying process, the moisture in the adhesive can be dried to avoid affecting the vacuum efficiency of the furnace after entering the furnace, while reducing the splashing of the solder.

[0050] The powdered solder is prepared by a gas atomization process; the parameters of the gas atomization process are: a melting temperature of 1390-1590° C.; a powder spraying temperature of 1410-1570° C.; an atomizing gas of argon; and an atomizing pressure of 4-10 MPa.

[0051] If a component with a complex inner cavity structure is divided into multiple parts and each of them is printed by additive manufacturing, the original inner cavity can be exposed to become the outer surface, and then the inner cavity can be machined into the required size and roughness by machining. Then, based on the above method, the separately printed additively manufactured high-temperature alloy parts are connected by a transient liquid phase connection process to obtain a complete component with a complex structure and high surface quality, thereby solving the problem of poor inner cavity and surface finish of additive manufacturing. At the same time, no support material is required to ensure the dimensional accuracy of the inner cavity, so there is no need to remove the support material, which reduces the process difficulty, improves the manufacturing qualification rate, and reduces the production cost.

[0052] Adding Cr to the intermediate layer solder can improve the oxidation resistance and corrosion resistance of the weld and play a role in solid solution strengthening; adding W can enhance the solid solution strengthening effect; in addition, in addition to B, adding auxiliary melting reduction elements Hf and Zr can reduce the melting point of the solder while also playing a role in solid solution strengthening the weld matrix, thereby improving the strength of the joint, and the introduction of Hf and Zr can reduce the amount of B added, thereby avoiding local stress concentration caused by excessive B element enrichment, and reducing the cracking sensitivity of strain aging cracks and ductile loss plastic cracks of the components after welding; the addition of the above alloying elements can make the intermediate layer solder have excellent connection processability; at the same time, the weld matrix maintains a single-phase γ solid solution with a large mismatch and low stacking fault energy, and avoids the precipitation of other second phases except the γ′ precipitation strengthening phase. B, Hf, and Zr elements are melting point reducing elements, which improve the connection processability; Cr and W elements increase the mismatch (i.e., the mismatch is more negative) and reduce the stacking fault energy; based on the composition of the solder in this application, no brittle second phase will precipitate in the weld, thereby maintaining a single-phase γ solid solution and ensuring the mechanical properties of the alloy after welding.

[0053] Based on the base material of the present application, the microstructure stability at 1020-1040°C is good. Long-term heat preservation annealing at this temperature can effectively reduce the residual stress of the base material without introducing additional harmful phases. If the temperature is lower, the stress release annealing effect is poor. If the temperature is higher, the degradation of the γ′ strengthening phase in the base material will be accelerated, thereby affecting the performance of the base material itself.

[0054] The intermediate layer alloy adds tungsten (W) with a content similar to that of the parent material and chromium (Cr) with a content slightly higher than that of the parent material to enhance the high-temperature strength of the weld matrix and improve oxidation resistance; the addition of hafnium (Hf) similar to that of the parent material can also improve the matching with the parent material while assisting in lowering the melting point of the joint and purifying the joint structure. In addition, boron (B) and zirconium (Zr) are introduced as melting reduction elements to optimize the melting temperature range, improve the fluidity and wettability of the powder, and thus improve the process performance of the connection area. The intermediate layer solder used in this application avoids the aggravation of stress concentration on the joint by conventional solders and avoids the formation of complex compound phases in the weld. While achieving a low stress state of the entire joint, a weld with no brittle compounds, good organizational stability and high strength is obtained, thereby ensuring excellent high-temperature mechanical properties.

[0055] On the other hand, the present invention provides an additively manufactured high-temperature alloy component, which is a welded part obtained by any of the above-mentioned welding methods; no non-isothermal solidification structure (harmful second phase) is observed at the weld of the additively manufactured high-temperature alloy component, and the microstructure at the weld includes γ phase and γ′ phase; the γ′ phase is uniformly dispersed in the weld; the γ′ phase is nearly cubic, and the volume fraction of the γ′ phase is 45-55%; among them, the γ′ precipitate phase with higher cubicity and larger volume fraction is more helpful to increase the resistance to dislocation movement at high temperature, and it is more difficult for dislocations to pass through these γ′ precipitate phases, thereby greatly improving the high-temperature strength of the joint; the shear strength of the additively manufactured high-temperature alloy component at 980°C is greater than or equal to 320MPa.

[0056] The present invention is further described below with reference to specific embodiments and comparative examples.

[0057] Example 1

[0058] This embodiment provides a transient connection method for additive high-temperature alloy parts, and the welding method includes the following steps:

[0059] Step 1): The to-be-welded portion of the first base material and the to-be-welded portion of the second base material are processed to a surface roughness of Ra0.4; then the oil stains of the to-be-welded portion are cleaned with anhydrous ethanol; the to-be-welded area is fixed by spot welding, and the to-be-welded gap is controlled to be 0.07 mm; then the powdered solder and the Nicorobraz s-binder adhesive are uniformly mixed in a mass ratio of 90%:10% to obtain a solder paste; then the solder paste is applied to an area within 2 mm from the to-be-welded area (set area); the coating amount is 4 times the volume of the to-be-welded area;

[0060] Applying Nicorobraz White stop-off TYPE II stopper to the non-to-be-welded portion of the first base material and the second base material, wherein the coating position is no more than 1.6 mm away from the maximum distance of the intermediate layer solder, and the stopper does not contact the intermediate layer alloy solder, and obtaining the parts to be welded;

[0061] The first parent material and the second parent material are both additive high-temperature alloy parts prepared by laser selective melting process; the chemical compositions of the first parent material and the second parent material are: Cr8%, Co8%, W8%, Mo2.2%, Al5.7%, Ti1%, Ta5.5%, C0.05%, B0.015%, Ni balance;

[0062] The chemical composition of the middle layer solder is as follows by weight percentage: Cr14%, W7%, B2.7%, Hf1.5%, Zr1.5%, and Ni balance; the particle size of the powder solder is not greater than 100μm; the powder solder is prepared by a gas atomization process; the parameters of the gas atomization process are: melting temperature is 1550℃; powder spraying temperature is 1520℃; atomizing gas is argon; and atomizing pressure is 8MPa.

[0063] Step 2): Place the parts to be welded in a drying oven for drying at a temperature of 100°C for 1 hour; then place them in a vacuum brazing furnace for annealing and connection treatment in sequence, and then cool them to 80°C and take them out of the furnace to obtain additively manufactured high-temperature alloy components; wherein the annealing temperature is 1030°C; the annealing time is 220 minutes; the connection temperature is 1160°C; the connection time is 240 minutes; the atmosphere in the furnace is vacuum or argon.

[0064] The joint of the additively manufactured high-temperature alloy component obtained in this embodiment was analyzed, and its microstructure is as follows: Figure 1 As shown, it can be seen that the weld has a dense structure, the matrix in the weld area is a γ solid solution, there is no non-isothermal solidification structure, and the shear strength of the additively manufactured high-temperature alloy component at 980°C is 370MPa.

[0065] Example 2

[0066] This embodiment provides a transient connection method for additive high-temperature alloy parts, and the welding method includes the following steps:

[0067] Step 1): The to-be-welded portion of the first base material and the to-be-welded portion of the second base material are processed to a surface roughness of Ra0.4; then the oil stains of the to-be-welded portion are cleaned with anhydrous ethanol; then two layers of foil strip intermediate layer solder are placed inside the to-be-welded area in a stacked form, the to-be-welded area is fixed by spot welding, and the to-be-welded gap is controlled to be 0.06 mm; and the foil strip solder is spot welded in an area within 2 mm from the to-be-welded area (set area); wherein the amount of foil strip solder in the set area is 1.5 times the amount of foil strip solder inside the to-be-welded area;

[0068] Applying Nicorobraz White stop-off TYPE II stopper to the non-to-be-welded portion of the first base material and the second base material, wherein the coating position is no more than 1.5 mm away from the farthest point of the intermediate layer solder, and the stopper does not contact the intermediate layer alloy solder, and obtaining the parts to be welded;

[0069] The first parent material and the second parent material are both precipitation-strengthened nickel-based high-temperature alloy Mar-Mar247 prepared by laser selective melting process; the chemical composition of Mar-Mar247 is: Cr8.25%, Co10%, W10%, Al5.5%, Hf1.5%, Ta1.5%, Ti1%, Mo0.7%, C0.15%, Ni balance in terms of mass percentage;

[0070] The chemical composition of the middle layer solder is as follows by weight percentage: Cr16%, W6%, B2.9%, Hf0.8%, Zr1.8%, and Ni balance; the above-mentioned foil strip solder is prepared by melt rapid quenching process; the parameters of the melt rapid quenching process are: melting temperature of 1540°C; spraying temperature of 1490°C; roller surface linear speed of 28m / s; and the distance between the nozzle and the roller surface is 0.3mm.

[0071] Step 2): Place the parts to be welded in a drying oven for drying at a temperature of 90°C for 40 minutes; then place them in a vacuum brazing furnace for annealing and connection treatment in sequence, and then cool them to 80°C and take them out of the furnace to obtain additively manufactured high-temperature alloy components; wherein the annealing temperature is 1020°C; the annealing time is 80 minutes; the connection temperature is 1130°C; the connection time is 120 minutes; the atmosphere in the furnace is vacuum or argon.

[0072] The joints of the additively manufactured high-temperature alloy components obtained in this embodiment were analyzed. The welds had dense structures, no non-isothermal solidification structures existed in the weld area, and the shear strength of the additively manufactured high-temperature alloy components obtained at 980°C was 339 MPa.

[0073] Example 3

[0074] This embodiment provides a transient connection method for additive high-temperature alloy parts, and the welding method includes the following steps:

[0075] Step 1): The to-be-welded portion of the first base material and the to-be-welded portion of the second base material are processed to a surface roughness of Ra0.4; then the oil stains of the to-be-welded portion are cleaned with anhydrous ethanol; the to-be-welded area is fixed by spot welding, and the to-be-welded gap is controlled to be 0.05 mm; then the powdered solder and the Nicorobraz s-binder adhesive are uniformly mixed in a mass ratio of 90%:10% to obtain a solder paste; then the solder paste is applied to an area within 2 mm from the to-be-welded area (set area); the coating amount is 3.5 times the volume of the to-be-welded area;

[0076] Applying Nicorobraz White stop-off TYPE II stopper to the non-to-be-welded portion of the first base material and the second base material, wherein the coating position is no more than 1.8 mm away from the maximum distance of the intermediate layer solder, and the stopper does not contact the intermediate layer alloy solder, and obtaining a part to be welded;

[0077] Among them, the first parent material and the second parent material are both Inconel738LC prepared by laser selective melting process; in terms of mass percentage, the chemical composition of Inconel 738LC is: C0.1%, Cr16%, Co8.5%, W2.6%, Mo2.2%, Al3.4%, Ti3.5%, Nb0.8%, Ta1.7%, Ni balance;

[0078] The chemical composition of the middle layer solder is as follows by weight percentage: Cr16.5%, W8.5%, B1.9%, Hf2.8%, Zr2.5%, and Ni balance; the particle size of the powder solder is not greater than 100μm; the powder solder is prepared by a gas atomization process; the parameters of the gas atomization process are: melting temperature is 1570℃; powder spraying temperature is 1540℃; atomizing gas is argon; and atomizing pressure is 9MPa.

[0079] Step 2): Place the parts to be welded in a drying oven for drying at a temperature of 120°C for 1 hour; then place them in a vacuum brazing furnace for annealing and connection treatment in sequence, and then cool them to 80°C and take them out of the furnace to obtain additively manufactured high-temperature alloy components; wherein the annealing temperature is 1040°C; the annealing time is 200 minutes; the connection temperature is 1200°C; the connection time is 360 minutes; the atmosphere in the furnace is vacuum or argon.

[0080] The joints of the additively manufactured high-temperature alloy components obtained in this embodiment were analyzed. The welds had dense structures, no non-isothermal solidification structures existed in the weld area, and the shear strength of the additively manufactured high-temperature alloy components obtained at 980°C was 399 MPa.

[0081] Comparative Example 1

[0082] This comparative example provides a transient connection method for additive high-temperature alloy parts, and the welding method includes the following steps:

[0083] Step 1): The to-be-welded portion of the first base material and the to-be-welded portion of the second base material are processed to a surface roughness of Ra0.4; then the oil stains of the to-be-welded portion are cleaned with anhydrous ethanol; the to-be-welded area is fixed by spot welding, and the to-be-welded gap is controlled to be 0.15 mm; then the powdered solder and the Nicorobraz s-binder adhesive are uniformly mixed in a mass ratio of 90%:10% to obtain a solder paste; then the solder paste is applied to an area within 2 mm from the to-be-welded area (set area); the coating amount is 4 times the volume of the to-be-welded area;

[0084] Applying Nicorobraz White stop-off TYPE II stopper to the non-to-be-welded portion of the first base material and the second base material, wherein the coating position is no more than 1.6 mm away from the maximum distance of the intermediate layer solder, and the stopper does not contact the intermediate layer alloy solder, and obtaining the parts to be welded;

[0085] The first parent material and the second parent material are both additive high-temperature alloy parts prepared by laser selective melting process; the chemical compositions of the first parent material and the second parent material are: Cr8%, Co8%, W8%, Mo2.2%, Al5.7%, Ti1%, Ta5.5%, C0.05%, B0.015%, Ni balance;

[0086] The chemical composition of the middle layer solder is as follows by weight percentage: Cr14%, W7%, B2.7%, Hf1.5%, Zr1.5%, and Ni balance; the particle size of the powder solder is not greater than 100μm; the powder solder is prepared by a gas atomization process; the parameters of the gas atomization process are: melting temperature is 1550℃; powder spraying temperature is 1520℃; atomizing gas is argon; and atomizing pressure is 8MPa.

[0087] Step 2): Place the parts to be welded in a drying oven for drying at a temperature of 100°C for 1 hour; then place them in a vacuum brazing furnace for annealing and connection treatment in sequence, and then cool them to 80°C and take them out of the furnace to obtain additively manufactured high-temperature alloy components; wherein the annealing temperature is 1030°C; the annealing time is 220 minutes; the connection temperature is 1160°C; the connection time is 240 minutes; the atmosphere in the furnace is vacuum or argon.

[0088] The joint of the additively manufactured high-temperature alloy component obtained in this comparative example was analyzed, and its microstructure is as follows Figure 2 As shown, it can be seen that the matrix of the weld zone is an isothermally solidified γ solid solution and a non-isothermally solidified structure, and the shear strength of the obtained additively manufactured high-temperature alloy component at 980°C is 128MPa. This is because the gap to be welded in Comparative Example 1 is large, resulting in failure to complete isothermal solidification during the connection process. At the end of the connection process, there is still a certain amount of residual liquid phase in the gap. These residual liquid phases solidify during the cooling process to form a non-isothermal solidification structure with a large number of network eutectics, which reduces the temperature bearing capacity of the joint, thereby reducing the shear strength of the joint.

[0089] Comparative Example 2

[0090] This comparative example provides a transient connection method for additive high-temperature alloy parts, and the welding method includes the following steps:

[0091] Step 1): The to-be-welded portion of the first base material and the to-be-welded portion of the second base material are processed to a surface roughness of Ra0.4; then the oil stains of the to-be-welded portion are cleaned with anhydrous ethanol; the to-be-welded area is fixed by spot welding, and the to-be-welded gap is controlled to be 0.07 mm; then the powdered solder and the Nicorobraz s-binder adhesive are uniformly mixed in a mass ratio of 90%:10% to obtain a solder paste; then the solder paste is applied to an area within 2 mm from the to-be-welded area (set area); the coating amount is 4 times the volume of the to-be-welded area;

[0092] Applying Nicorobraz White stop-off TYPE II stopper to the non-to-be-welded portion of the first base material and the second base material, wherein the coating position is no more than 1.6 mm away from the maximum distance of the intermediate layer solder, and the stopper does not contact the intermediate layer alloy solder, and obtaining the parts to be welded;

[0093] The first parent material and the second parent material are both additive high-temperature alloy parts prepared by laser selective melting process; the chemical compositions of the first parent material and the second parent material are: Cr8%, Co8%, W8%, Mo2.2%, Al5.7%, Ti1%, Ta5.5%, C0.05%, B0.015%, Ni balance;

[0094] The chemical composition of the middle layer solder is as follows by weight percentage: Cr14%, W7%, B2.7%, Hf1.5%, Zr1.5%, and Ni balance; the particle size of the powder solder is not greater than 100μm; the powder solder is prepared by a gas atomization process; the parameters of the gas atomization process are: melting temperature is 1550℃; powder spraying temperature is 1520℃; atomizing gas is argon; and atomizing pressure is 8MPa.

[0095] Step 2): Place the parts to be welded in a drying oven for drying at a temperature of 100°C for 1 hour; then place them in a vacuum brazing furnace for annealing and connection treatment in sequence, and then cool them to 80°C and take them out of the furnace to obtain additively manufactured high-temperature alloy components; wherein the annealing temperature is 1030°C; the annealing time is 20 minutes; the connection temperature is 1160°C; the connection time is 240 minutes; the atmosphere in the furnace is vacuum or argon.

[0096] The joint of the additively manufactured high-temperature alloy component obtained in this comparative example was analyzed, and its microstructure is as follows Figure 3 As shown, it can be seen that there is no non-isothermal solidification structure in the weld zone, but solid cracks appear in the diffusion-affected zone of the parent material, and the shear strength of the obtained additively manufactured high-temperature alloy component at 980°C is 165MPa. In this comparative example, the annealing time is only 20 minutes, which fails to fully eliminate the residual stress of the parent material. In the subsequent connection process, the further interaction between the solder and the parent material elements further aggravates the stress state, resulting in solid cracks in the diffusion-affected zone of the parent material, thereby affecting the shear strength of the joint.

[0097] Comparative Example 3

[0098] This comparative example provides a transient connection method for additive high-temperature alloy parts, and the welding method includes the following steps:

[0099] Step 1): The to-be-welded portion of the first base material and the to-be-welded portion of the second base material are processed to a surface roughness of Ra0.4; then the oil stains of the to-be-welded portion are cleaned with anhydrous ethanol; the to-be-welded area is fixed by spot welding, and the to-be-welded gap is controlled to be 0.07 mm; then the powdered solder and the Nicorobraz s-binder adhesive are uniformly mixed in a mass ratio of 90%:10% to obtain a solder paste; then the solder paste is applied to an area within 2 mm from the to-be-welded area (set area); the coating amount is 4 times the volume of the to-be-welded area;

[0100] Applying Nicorobraz White stop-off TYPE II stopper to the non-to-be-welded portion of the first base material and the second base material, wherein the coating position is no more than 1.6 mm away from the maximum distance of the intermediate layer solder, and the stopper does not contact the intermediate layer alloy solder, and obtaining the parts to be welded;

[0101] The first parent material and the second parent material are both additive high-temperature alloy parts prepared by laser selective melting process; the chemical compositions of the first parent material and the second parent material are: Cr8%, Co8%, W8%, Mo2.2%, Al5.7%, Ti1%, Ta5.5%, C0.05%, B0.015%, Ni balance;

[0102] The chemical composition of the intermediate layer solder is as follows by weight percentage: Cr14%, W7%, B4.1%, and Ni balance; the particle size of the powder solder is not greater than 100 μm; the powder solder is prepared by a gas atomization process; the parameters of the gas atomization process are: melting temperature is 1550°C; powder spraying temperature is 1520°C; atomizing gas is argon; and atomizing pressure is 8 MPa.

[0103] Step 2): Place the parts to be welded in a drying oven for drying at a temperature of 100°C for 1 hour; then place them in a vacuum brazing furnace for annealing and connection treatment in sequence, and then cool them to 80°C and take them out of the furnace to obtain additively manufactured high-temperature alloy components; wherein the annealing temperature is 1030°C; the annealing time is 220 minutes; the connection temperature is 1160°C; the connection time is 240 minutes; the atmosphere in the furnace is vacuum or argon.

[0104] The joints of the additively manufactured high-temperature alloy components obtained in this comparative example were analyzed. It was found that there was no non-isothermal solidification structure in the weld area. However, due to the excessive addition of the melting-reducing element B in the intermediate layer solder and the absence of Hf and Zr elements, the matrix strength was insufficient, and the shear strength of the additively manufactured high-temperature alloy components obtained at 980°C was 173 MPa.

[0105] It can be seen from the above-mentioned Examples 1-3 that the additively manufactured high-temperature alloys have successfully achieved transient liquid phase connection, the joints have no non-isothermal solidification structure, and the shear strength of the joints at 980°C is not less than 300 MPa, which shows that the transient liquid phase connection method of the present invention can achieve high-performance connection of additively manufactured high-temperature alloys.

[0106] It can be seen from the above comparative examples 1-3 that the shear strength of the joint at 980°C is lower than 300MPa, among which the non-isothermal solidification structure in the weld zone of comparative example 1 affects the joint performance, the solid cracks in the diffusion-affected zone of the joint parent material of comparative example 2 affect the joint performance, and the insufficient intrinsic strength of the weld matrix of comparative example 3 affects the overall performance of the joint. This shows that the high-performance transient liquid phase connection of additively manufactured high-temperature alloys cannot be successfully achieved when the solder composition exceeds the specified range, the brazing process parameters exceed the specified range, or the gap to be welded exceeds the specified range.

[0107] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A transient liquid phase joining method for additive high temperature alloy parts, characterized in that: The welding method comprises the following steps: Step 1): adding an intermediate layer of solder to the area to be welded to obtain a part to be welded; wherein the area to be welded is formed by a portion to be welded of the first parent material and a portion to be welded of the second parent material being arranged relatively spaced apart; Wherein, the first parent material and the second parent material are both additive high temperature alloy parts; Step 2): performing transient liquid phase connection treatment on the parts to be welded, so that the first base material, the intermediate layer solder, and the second base material are connected together; Wherein, the chemical composition of the intermediate layer solder is, by weight percentage, Cr11%-17%, W5%-9%, B1%-3.5%, Hf0.3%-3%, Zr0.3%-3%, and Ni balance.

2. The transient connection method of additive high-temperature alloy parts according to claim 1, characterized in that: The intermediate layer solder is a foil strip solder; Preferably, the thickness of the foil strip solder is 0.02-0.06 mm.

3. The transient connection method of additive high-temperature alloy parts according to claim 2, characterized in that: The step of adding an intermediate layer of solder to the area to be welded comprises: placing the foil strip solder inside the area to be welded; preferably, further comprising: spot welding the foil strip solder in a set area; wherein the set area is an area within 2 mm from the area to be welded; further preferably, the amount of the foil strip solder in the set area is greater than or equal to the amount of the foil strip solder inside the area to be welded; and / or The foil strip solder is prepared by a melt rapid quenching process; preferably, the parameters of the melt rapid quenching process are: melting temperature of 1390-1590°C; spraying temperature of 1410-1510°C; roller surface linear speed of 20-35m / s; and the distance between the nozzle and the roller surface of 0.2-0.4mm.

4. The transient connection method of additive high-temperature alloy parts according to claim 1, characterized in that: The intermediate layer solder is powdered solder; Preferably, the particle size of the powdered solder is less than or equal to 100 μm.

5. The transient connection method of additive high temperature alloy parts according to claim 4, characterized in that: The step of adding an intermediate layer of solder to the area to be soldered comprises: mixing the powdered solder with an adhesive to obtain a solder paste; and then placing the solder paste in a set area; wherein the set area is an area within 2 mm from the area to be soldered; preferably, the mass ratio of the powdered solder in the solder paste is 87%-93%; the volume of the solder paste in the set area is not less than 3 times the volume of the area to be soldered; and / or The powdered solder is prepared by a gas atomization process; preferably, the parameters of the gas atomization process are: melting temperature is 1390-1590°C; powder spraying temperature is 1410-1570°C; atomizing gas is argon; and atomizing pressure is 4-10MPa.

6. The transient connection method of additive high temperature alloy parts according to claim 1, characterized in that: The chemical composition of the first parent material is, by weight percentage, Cr 6%-16%, Co 6%-10%, W 6%-11%, Mo 0.5%-3%, Al 3%-6%, Ti 0.5%-3.6%, Ta 1%-6%, Nb 0-1%, C ≤ 0.2%, B ≤ 0.1%, Hf ≤ 2%, Ni balance; and / or The chemical composition of the second parent material is, by weight percentage, Cr 6%-16%, Co 6%-10%, W 6%-11%, Mo 0.5%-3%, Al 3%-6%, Ti 0.5%-3.6%, Ta 1%-6%, Nb 0-1%, C ≤ 0.2%, B ≤ 0.1%, Hf ≤ 2%, Ni balance; and / or The additively manufactured high-temperature alloy part is prepared by a laser selective melting process or a laser melting deposition process.

7. The transient connection method of additive high temperature alloy parts according to claim 1, characterized in that: In the step 1), the surface roughness of the to-be-welded portion of the first base material is Ra0.2-Ra0.8; and / or The surface roughness of the to-be-welded portion of the second base material is Ra0.2-Ra0.8; and / or The gap to be welded is less than or equal to 0.08 mm; and / or After the step of adding an intermediate layer of solder to the area to be welded, the method further includes: coating a flow blocker on the non-welded parts of the first and second base materials; preferably, the flow blocker is not in contact with the intermediate layer of solder, and the distance between the coating position of the flow blocker and the intermediate layer of solder is less than or equal to 2 mm.

8. The transient connection method of additive high temperature alloy parts according to claim 1, characterized in that: In the step 2): a vacuum heat treatment furnace or a vacuum brazing furnace is used to perform transient liquid phase connection treatment; preferably, the atmosphere in the furnace is vacuum or argon; and / or Before the step of transient liquid phase connection treatment, the method further includes: drying the parts to be connected; the drying temperature is 90-120° C.; the drying time is 40-60 minutes; and / or After the step of transient liquid phase connection treatment, the method further includes: cooling treatment; preferably, the cooling treatment adopts a furnace cooling method.

9. The transient connection method of additive high temperature alloy parts according to claim 1, characterized in that: The transient liquid phase connection process includes an annealing process and a connection process performed sequentially; Preferably, the annealing temperature is 1020-1040°C; the annealing time is 60-240min; Preferably, the temperature of the connection treatment is 1120-1200° C.; and the time of the connection treatment is 100-360 min.

10. An additively manufactured high-temperature alloy component, characterized in that: The additively manufactured high-temperature alloy component is a welded part obtained by the welding method described in any one of claims 1 to 9; Preferably, no non-isothermal solidification structure is observed at the weld of the additively manufactured high-temperature alloy component; the microstructure at the weld includes a γ phase and a γ′ phase; the γ′ phase is uniformly dispersed at the weld; the γ′ phase is nearly cubic, and the volume fraction of the γ′ phase is 45-55%; Preferably, the shear strength of the additively manufactured high-temperature alloy component at 980° C. is greater than or equal to 320 MPa.

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