Transient liquid phase bonding of additively manufactured superalloy components and additively manufactured superalloy components

Abstract

The application provides a kind of additive high-temperature alloy piece transient connection method and additive manufacturing high-temperature alloy piece, it is related to high-temperature alloy connection technical field, welding method includes the following steps: adding interlayer solder in the area to be welded, obtains the piece to be welded;Wherein, the area to be welded is the first base material and the second base material are arranged oppositely and spaced to form;Wherein, the first base material and the second base material are all additive high-temperature alloy pieces;The piece to be welded is treated by transient liquid phase connection, so that the first base material, interlayer solder and the second base material are connected together;Wherein, the chemical composition of interlayer solder is: Cr 11%-17%, W 5%-9%, B 1%-3.5%, Hf 0.3%-3%, Zr 0.3%-3%, Ni balance in percentage by weight.The application connects the additive manufacturing high-temperature alloy pieces printed respectively by transient liquid phase connection process, obtains complete component with complex structure and high surface quality, thereby solving the problem of poor surface finish and internal cavity of additive manufacturing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-temperature alloy connection, and particularly relates to a transient liquid phase connection method of additive high-temperature alloy and a joint. BACKGROUND

[0002] The additive manufacturing high-temperature alloy is printed into a high-temperature alloy by adopting the powder laying or powder feeding mode of high-temperature alloy powder with a suitable particle size, so as to realize a shorter manufacturing cycle, lower manufacturing cost and less raw material consumption than the traditional casting and forging technology, and has been widely applied to the production of various parts of an aero-engine and a gas turbine.

[0003] However, due to the limitation of the prior art, the smoothness of the inner cavity and the outer surface of the high-temperature alloy component is greatly different from that of the traditional investment casting process, and when the inner cavity structure of a part with high dimensional accuracy is manufactured, a support material must be used to ensure the dimensional accuracy of the inner cavity, and if the inner cavity structure is complex, the support material cannot be removed after manufacturing. SUMMARY

[0004] Therefore, the application provides a transient liquid phase connection method of additive high-temperature alloy and a joint, which can solve the problem of poor smoothness of the inner cavity and the outer surface of the additive manufacturing high-temperature alloy component in the prior art.

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

[0006] Step 1): adding an intermediate layer solder to a welding area to obtain a welding part; wherein the welding area is formed by oppositely arranging a welding part of a first base material and a welding part of a second base material;

[0007] The first base material and the second base material are both additive high-temperature alloy parts.

[0008] Step 2): performing transient liquid phase connection treatment on the welding part to connect the first base material, the intermediate layer solder and the second base material together.

[0009] The chemical composition of the intermediate layer solder is: Cr 11%-17%, W 5%-9%, B 1%-3.5%, Hf 0.3%-3%, Zr 0.3%-3%, and Ni balance, in terms of weight percentage.

[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 the intermediate layer solder to the to-be-welded area comprises: placing the foil-shaped solder inside the to-be-welded area; preferably, further comprising: spot-welding the foil-shaped solder in a set area; wherein the set area is an area within 2 mm from the to-be-welded area; further preferably, the amount of the foil-shaped solder in the set area is greater than or equal to the amount of the foil-shaped solder inside the to-be-welded area; and / or

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

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

[0015] Further, the step of adding the intermediate layer solder to the to-be-welded area comprises: mixing the powdery 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 to-be-welded area; preferably, in the solder paste, the mass ratio of the powdery solder is 87%-93%; and the volume of the solder paste in the set area is not less than 3 times the volume of the to-be-welded area; and / or

[0016] The powdery solder is prepared by a gas atomization process; preferably, the parameters of the gas atomization process are: a smelting temperature of 1390-1590 ℃; a powder spraying temperature of 1410-1570 ℃; an atomization gas of argon; and an atomization pressure of 4-10 MPa.

[0017] Further, the chemical composition of the first base material, in terms of percentage by weight, is: 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%, and Ni balance; and / or

[0018] The chemical composition of the second base material, in terms of percentage by weight, is: 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%, and Ni balance; and / or

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

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

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

[0022] the to-be-welding gap is less than or equal to 0.08 mm; and / or

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

[0024] Further, in the step 2), the transient liquid phase connection treatment is performed by using a vacuum heat treatment furnace or a vacuum brazing furnace; preferably, the atmosphere in the furnace is vacuum or argon; and / or

[0025] Before the step of the transient liquid phase connection treatment, further comprising: performing a drying treatment on the to-be-connected parts; the temperature of the drying treatment is 90-120℃; the time of the drying treatment is 40-60 min; and / or

[0026] After the step of the transient liquid phase connection treatment, further comprising: a cooling treatment; preferably, the cooling treatment is performed by using a furnace cooling method.

[0027] Further, the transient liquid phase connection treatment comprises an annealing treatment and a connection treatment performed in sequence; preferably, the temperature of the annealing treatment is 1020-1040℃; the time of the annealing treatment is 60-240 min; preferably, the temperature of the connection treatment is 1120-1200℃; the time of the connection treatment is 100-360 min.

[0028] In the weld of the additive manufacturing high-temperature alloy component, no non-isothermal solidification structure is observed; the microstructure of the weld comprises γ phase and γ' phase; the γ' phase is uniformly and dispersedly distributed in the weld; the γ' phase is in a near-cubic shape, and the volume fraction of the γ' phase is 45-55%;

[0029] Preferably, the shear strength of the additive manufacturing high-temperature alloy component at 980℃ is greater than or equal to 320 MPa.

[0030] The additive high-temperature alloy part transient connection method and the additive manufacturing high-temperature alloy component provided by the application have the following beneficial effects:

[0031] 1. The present application provides a kind of additive high temperature alloy piece transient connection method, comprising the following steps: adding interlayer solder in the welding area, obtain the welding piece;Wherein, the welding area is the welding part of first base material and the welding part of second base material opposite interval setting formation;Wherein, first base material and second base material are all additive high temperature alloy piece;To the welding piece is carried out transient liquid phase connection processing, so that first base material, interlayer solder, second base material are connected together;It needs to be explained that, the component is split into multiple parts, and the multiple parts are obtained by additive manufacturing, the original inner cavity is exposed to become outer surface, and the inner cavity is machined into the required size and required finish by machining method, based on the above method, the additive manufacturing high temperature alloy piece printed respectively is connected by transient liquid phase connection process, to obtain complete component with complex structure and high surface quality, so as to solve the problem of poor inner cavity and surface finish of additive manufacturing;At the same time, no support material is needed to ensure the size accuracy of inner cavity, so no support material is needed to be removed, the process difficulty is reduced, the manufacturing qualification rate is improved, and the production cost is reduced.

[0032] 2. Further, in the interlayer solder, Cr element can be added to improve the oxidation resistance, corrosion resistance of weld and play a solid solution strengthening effect;W element can be added to strengthen the solid solution strengthening effect;In addition, in addition to B element, auxiliary melting element Hf and Zr are added, which can not only reduce the melting point of the solder, but also play a role in solid solution strengthening the weld base body, thereby improving the strength of the joint, and the introduction of Hf and Zr can reduce the addition amount of B element, thereby avoiding the local stress concentration caused by excessive B element enrichment, and reducing the cracking sensitivity of strain aging crack and ductility loss crack of the component after welding;The addition of the above alloy elements can make the interlayer solder have excellent connection process;At the same time, the weld base body remains single-phase γ solid solution with large mismatch degree and low dislocation, and avoids the precipitation of other second phases except γ' precipitation strengthening phase, thereby facilitating to ensure the mechanical properties of the joint after welding.

[0033] 3. Further, by annealing treatment, the original γ' phase of first base material and second base material is first dissolved, and the internal stress is released, then the element interdiffusion is realized by connection treatment, to obtain high-performance dense joint, and γ' precipitation strengthening phase is reprecipitated in weld and base material during cooling process;Wherein, during the connection process, the weld and the base material are in low stress state, and the connection process is completed in low strength and high plasticity state, avoiding the influence of stress on the connection process, and the joint after connection regains high strength structure.

[0034] 4. In another aspect, the present application provides an additively manufactured superalloy component, which is a welded piece obtained by the welding method according to any one of the above aspects; no non-isothermal solidification structure is observed at the weld of the additively manufactured superalloy component; and the shear strength at 980℃ is greater than or equal to 320MPa; the additively manufactured superalloy component is obtained by the method. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in the following description are merely exemplary, and other drawings can also be obtained according to the provided drawings without creative labor for those skilled in the art.

[0036] Figure 1 is a micrograph of the additively manufactured superalloy component obtained by Example 1 of the present application;

[0037] Figure 2 is a micrograph of the additively manufactured superalloy component obtained by Comparative Example 1 of the present application;

[0038] Figure 3 is a micrograph of the additively manufactured superalloy component obtained by Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in the following description are merely exemplary, and other drawings can also be obtained according to the provided drawings without creative labor for those skilled in the art.

[0040] The present application provides a transient connection method for an additively manufactured superalloy component, and the welding method comprises the following steps:

[0041] Step 1): adding an intermediate layer solder to the welding area, and then coating a flow inhibitor on the non-welding part of the first base material and the second base material to obtain a welding piece; wherein the welding area is formed by oppositely spacing the welding part of the first base material and the welding part of the second base material;

[0042] The step is specifically: machining the to-be-welded part of the first base material and the to-be-welded part of the second base material to have a surface roughness of Ra0.2-Ra0.8; cleaning the to-be-welded part with anhydrous ethanol or acetone; then adding an intermediate layer solder to the to-be-welded area, and coating a flow inhibitor on the non-to-be-welded part of the first base material and the second base material to obtain a to-be-welded piece; wherein the surface roughness of the to-be-welded part of the first base material and the second base material is limited to Ra0.2-Ra0.8 to avoid that the surface is too rough or too smooth to affect the gap filling ability of the solder.

[0043] The flow inhibitor is not in contact with the intermediate layer solder, and the distance between the coating position of the flow inhibitor and the intermediate layer solder is less than or equal to 2 mm; the to-be-welded gap is less than or equal to 0.08 mm; the first base material and the second base material are both additive high-temperature alloy pieces prepared by a laser selective melting process or a laser melting deposition process; the chemical composition of the first base material and the second base material, in terms of weight percentage, is: 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; wherein the flow inhibitor prevents the solder from flowing to the non-to-be-welded part; the flow inhibitor can be an alumina-based flow inhibitor or a chromium oxide-based flow inhibitor, and the alumina-based flow inhibitor is used in the present application for easy removal; if the to-be-welded gap is too large, it is difficult to achieve complete isothermal solidification during the annealing holding process, thereby forming a non-equilibrium solidification zone in the weld, and low-melting-point eutectic structures exist in the zone, thereby affecting the mechanical properties of the joint after welding.

[0044] The chemical composition of the intermediate layer solder, in terms of weight percentage, is: Cr 11%-17%, W 5%-9%, B 1%-3.5%, Hf 0.3%-3%, Zr 0.3%-3%, Ni balance.

[0045] Step 2): performing transient liquid phase bonding treatment on the to-be-welded piece to connect the first base material, the intermediate layer solder, and the second base material together.

[0046] The step is specifically: after drying treatment of the to-be-welded parts in a drying box, sequentially performing annealing treatment and connecting treatment in a vacuum heat treatment furnace or a vacuum brazing furnace, and then performing furnace cooling treatment; wherein, the temperature of the drying treatment is 90-120℃; the time of the drying treatment is 40-60min; the temperature of the annealing treatment is 1020-1040℃; the time of the annealing treatment is 60-240min; the temperature of the connecting treatment is 1120-1200℃; the time of the connecting treatment is 100-360min; the atmosphere in the furnace is vacuum or argon; wherein, the furnace cooling treatment is to cool to below 80℃ and then take out the furnace. The slow cooling speed of the furnace cooling treatment can avoid cracking of the joint or the base material; the purpose of taking out the furnace below 80℃ is to avoid oxidation of the parts and the furnace caused by too high temperature.

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

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

[0049] In some embodiments, the intermediate layer solder is a powdery solder; the particle size of the powdery solder is less than or equal to 100μm, which is convenient for subsequent mixing, placing in a set area, etc. of the solder; the step of adding the intermediate layer solder to the to-be-welded area includes: mixing the powdery 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 2mm from the to-be-welded area; in the solder paste, the mass ratio of the powdery solder is 87%-93%; the volume of the solder paste in the set area is not less than 3 times the volume of the to-be-welded area. The solder paste is placed in the set area to avoid excessive melting of the non-welding area; the adhesive can use water-based adhesive or oily adhesive. Through the above drying treatment, the water in the adhesive can be dried, which avoids affecting the vacuum efficiency of the furnace after entering the furnace, and reduces the splashing phenomenon of the solder.

[0050] The powdery solder is prepared by gas atomization process; the parameters of the gas atomization process are: smelting temperature is 1390-1590℃; powder spraying temperature is 1410-1570℃; atomizing gas is argon; atomizing pressure is 4-10MPa.

[0051] If the component with complex internal cavity structure is divided into multiple parts, each part is printed by additive manufacturing, the original internal cavity is exposed to become an external surface, and then the internal cavity is machined to the required size and roughness, and then the separately printed additive manufacturing superalloy parts are connected by transient liquid phase connection process based on the above method, so as to obtain a complete component with complex structure and high surface quality, thereby solving the problem of poor internal cavity and surface finish of additive manufacturing; at the same time, no support material is needed to ensure the internal cavity size accuracy, so no support material needs to be removed, thereby reducing the process difficulty, improving the manufacturing qualification rate, and reducing the production cost.

[0052] In the intermediate layer solder, the addition of Cr element can improve the oxidation resistance and corrosion resistance of the weld, and also has a solid solution strengthening effect; the addition of W element can enhance the solid solution strengthening effect; in addition, in addition to B element, the addition of auxiliary melting elements Hf and Zr can reduce the melting point of the solder while also having the effect of solid solution strengthening the weld matrix, thereby improving the strength of the joint, and the introduction of Hf and Zr can reduce the addition amount of B element, thereby avoiding the local stress concentration caused by excessive enrichment of B element, and reducing the cracking sensitivity of strain aging cracks and ductility loss cracks of the component after welding; the addition of the above alloying elements can make the intermediate layer solder have excellent connection process; at the same time, the weld matrix remains a single-phase γ solid solution with large mismatch degree and low dislocation energy, and avoids the precipitation of other second phases except for γ' precipitation strengthening phase. B, Hf and Zr elements are melting elements that improve the connection process; Cr and W elements increase the mismatch degree (i.e. more negative mismatch degree) and reduce the dislocation energy; based on the composition of the solder in the present application, no brittle second phase is precipitated 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℃ is good, long-time annealing at this temperature can effectively reduce the residual stress of the base material, and will not bring additional harmful phases; if the temperature is lower, the stress relief annealing effect is poor; if the temperature is higher, the γ' strengthening phase in the base material will be degraded, thereby affecting the performance of the base material itself.

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

[0055] In another aspect, the present application provides an additively manufactured high-temperature alloy component, which is a welded piece obtained by using any of the welding methods described above; 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 at the weld; the γ' phase is in a near-cubic shape, and the volume fraction of the γ' phase is 45-55%; wherein the γ' precipitated phase with higher cubic degree and larger volume fraction is more conducive to increasing the resistance to dislocation motion at high temperatures, and it is more difficult for dislocations to pass through these γ' precipitated phases, thereby greatly improving the high-temperature strength of the joint; the shear strength of the additively manufactured high-temperature alloy component at 980℃ is greater than or equal to 320MPa.

[0056] The present application will be further described below in conjunction with specific examples and comparative examples.

[0057] Example 1

[0058] The present embodiment provides a transient connection method for an additively manufactured high-temperature alloy component, and the welding method includes the following steps:

[0059] Step 1): Process the first base material to be welded and the second base material to be welded to a surface roughness of Ra0.4; then clean the oil stains on the to-be-welded part with anhydrous ethanol; use spot welding method to fix the to-be-welded area, and control the to-be-welded gap to be 0.07mm; then uniformly mix the powdery solder and Nicrobraz s-binder adhesive at a mass ratio of 90:10 to obtain a solder paste; then apply the solder paste to the area (set area) within 2mm from the to-be-welded area; the coating amount is 4 times the volume of the to-be-welded area;

[0060] Nicrobraz White stop-off TYPE II stop-off agent is applied to the non-welding part of the first base material and the second base material, the distance between the application position and the farthest position of the intermediate layer solder is not more than 1.6 mm, and the stop-off agent does not contact the intermediate layer alloy solder, and the welding part is obtained;

[0061] The first base material and the second base material are both additive high-temperature alloy parts prepared by a laser selective melting process; the chemical composition of the first base material and the second base material is: Cr 8%, Co 8%, W 8%, Mo 2.2%, Al 5.7%, Ti 1%, Ta 5.5%, C 0.05%, B 0.015%, and Ni balance;

[0062] The chemical composition of the intermediate layer solder is, by weight percentage: Cr 14%, W 7%, B 2.7%, Hf 1.5%, Zr 1.5%, and Ni balance; the particle size of the powdered solder is not greater than 100 μm; the powdered solder is prepared by a gas atomization process; the parameters of the gas atomization process are: a smelting temperature of 1550°C; a powder spraying temperature of 1520°C; an atomizing gas of argon; and an atomizing pressure of 8 MPa.

[0063] Step 2): The welding part is placed in a drying box for drying treatment, the drying treatment temperature is 100°C, and the drying treatment time is 1 h; then it is placed in a vacuum brazing furnace for annealing treatment and connection treatment in sequence, and then cooled to 80°C in the furnace to be taken out, to obtain an additive manufacturing high-temperature alloy component; wherein the annealing treatment temperature is 1030°C; the annealing treatment time is 220 min; the connection treatment temperature is 1160°C; the connection treatment time is 240 min; and the atmosphere in the furnace is vacuum or argon.

[0064] The joint of the additive manufacturing high-temperature alloy component obtained in this embodiment is analyzed, and the microstructure thereof is as shown in Figure 1 It can be seen that the microstructure of the welding seam is dense, the matrix of the welding seam area is a γ solid solution, there is no non-isothermal solidification structure, and the shear strength of the additive manufacturing high-temperature alloy component obtained at 980°C is 370 MPa.

[0065] Example 2

[0066] This embodiment provides a transient connection method of an additive high-temperature alloy part, and the welding method comprises the following steps:

[0067] Step 1): the to-be-welded part of the first base material and the to-be-welded part of the second base material are processed to have a surface roughness of Ra0.4; then the to-be-welded parts are cleaned of oil stains with anhydrous ethanol; then 2 layers of foil-shaped intermediate layer solder are placed in a stacked form inside the to-be-welded area, 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-shaped solder is spot-welded in a region (set region) within 2 mm from the to-be-welded area; wherein the amount of foil-shaped solder in the set region is 1.5 times the amount of foil-shaped solder inside the to-be-welded area;

[0068] Nicrobraz White stop-off TYPE II stop-off agent is applied to the non-to-be-welded parts of the first base material and the second base material, the distance from the application position to the farthest position of the intermediate layer solder is not more than 1.5 mm, and the stop-off agent does not contact the intermediate layer alloy solder, and a to-be-welded part is obtained;

[0069] The first base material and the second base material are both precipitation-strengthened nickel-based high-temperature alloy Mar-Mar247 prepared by a laser selective melting process; the chemical composition of the Mar-Mar247 is, in terms of mass percentage: Cr 8.25%, Co 10%, W 10%, Al 5.5%, Hf 1.5%, Ta 1.5%, Ti 1%, Mo 0.7%, C 0.15%, and Ni balance.

[0070] The chemical composition of the intermediate layer solder is, in terms of weight percentage: Cr 16%, W 6%, B 2.9%, Hf 0.8%, Zr 1.8%, and Ni balance; the foil-shaped solder is prepared by a melt quenching process; the parameters of the melt quenching process are: a smelting temperature of 1540°C; a spraying temperature of 1490°C; a roller surface linear velocity of 28 m / s; and a distance between the nozzle and the roller surface of 0.3 mm.

[0071] Step 2): the to-be-welded part is placed in a drying box for drying treatment, the drying treatment is performed at a temperature of 90°C for 40 min; then the to-be-welded part is sequentially subjected to annealing treatment and connection treatment in a vacuum brazing furnace, and then cooled to 80°C in the furnace to be taken out, thereby obtaining an additively manufactured high-temperature alloy component; wherein the annealing treatment is performed at a temperature of 1020°C for 80 min; the connection treatment is performed at a temperature of 1130°C for 120 min; and the atmosphere in the furnace is vacuum or argon.

[0072] The joint of the additively manufactured high-temperature alloy component obtained in this embodiment is analyzed, the weld structure is dense, there is no non-isothermal solidification structure in the weld area, and the shear strength of the additively manufactured high-temperature alloy component at 980°C is 339 MPa.

[0073] Example 3

[0074] The embodiment provides a method for transiently connecting an additive high-temperature alloy part, and the welding method comprises the following steps:

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

[0076] Nicrobraz White stop-off TYPE II stop-off agent is applied to the non-to-be-welded part of the first base material and the second base material, the farthest distance from the intermediate layer solder is not more than 1.8 mm, the stop-off agent does not contact the intermediate layer alloy solder, and a to-be-welded part is obtained.

[0077] The first base material and the second base material are both Inconel 738LC prepared by using a laser selective melting process; the chemical composition of the Inconel 738LC is as follows in terms of mass percentage: C 0.1%, Cr 16%, Co 8.5%, W 2.6%, Mo 2.2%, Al 3.4%, Ti 3.5%, Nb 0.8%, Ta 1.7%, and Ni balance.

[0078] The chemical composition of the intermediate layer solder is as follows in terms of weight percentage: Cr 16.5%, W 8.5%, B 1.9%, Hf 2.8%, Zr 2.5%, and Ni balance; the particle size of the powdered solder is not more than 100 μm; the powdered solder is prepared by using a gas atomization process; and the parameters of the gas atomization process are as follows: a smelting temperature is 1570 DEG C; a powder spraying temperature is 1540 DEG C; an atomization gas is argon; and an atomization pressure is 9 MPa.

[0079] Step 2): the to-be-welded part is placed in a drying box for drying treatment, the temperature of the drying treatment is 120 DEG C, and the time of the drying treatment is 1 h; then the to-be-welded part is sequentially subjected to annealing treatment and connection treatment in a vacuum brazing furnace, and then is cooled to 80 DEG C in the furnace to be taken out, so that an additive manufacturing high-temperature alloy component is obtained; the temperature of the annealing treatment is 1040 DEG C; the time of the annealing treatment is 200 min; the temperature of the connection treatment is 1200 DEG C; the time of the connection treatment is 360 min; and the atmosphere in the furnace is vacuum or argon.

[0080] The joint of the additively manufactured high-temperature alloy component obtained in the embodiment is analyzed, the microstructure of the weld is dense, there is no non-isothermal solidification microstructure in the weld zone, and the shear strength of the obtained additively manufactured high-temperature alloy component at 980℃ is 399MPa.

[0081] Comparative Example 1

[0082] The present comparative example provides a transient joining method of an additively manufactured high-temperature alloy component, and the welding method comprises the following steps:

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

[0084] Nicrobraz White stop-off TYPE II stop-off agent is applied to the non-to-be-welded part of the first base material and the second base material, the distance from the application position to the farthest part of the intermediate layer solder does not exceed 1.6mm, and the stop-off agent does not contact the intermediate layer alloy solder, and a to-be-welded part is obtained;

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

[0086] The chemical composition of the intermediate layer solder is: Cr14%, W7%, B2.7%, Hf1.5%, Zr1.5%, Ni balance, by weight percentage; the particle size of the powdered solder is not greater than 100μm; the powdered 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; atomizing pressure is 8MPa.

[0087] Step 2): Place the parts to be welded in a drying oven for drying at 100℃ for 1 hour; then place them in a vacuum brazing furnace for annealing and joining treatments in sequence, and then cool them in the furnace to 80℃ to obtain additive manufacturing high-temperature alloy components; wherein, the annealing temperature is 1030℃ and the annealing time is 220 minutes; the joining temperature is 1160℃ and the joining time is 240 minutes; the furnace atmosphere is vacuum or argon.

[0088] The microstructure of the joint of the additively manufactured high-temperature alloy component obtained in this comparative example is analyzed as follows: Figure 2 As shown, the weld zone matrix consists of isothermal solidified γ-solid solution and non-isothermal solidified structures, and the resulting additively manufactured high-temperature alloy component exhibits a shear strength of 128 MPa at 980 °C. This is because the gap to be welded in Comparative Example 1 was relatively large, resulting in incomplete isothermal solidification during the joining process. At the end of the joining process, a certain amount of residual liquid phase remained in the gap. These residual liquid phases solidified during the cooling process, forming a non-isothermal solidified structure with a large amount of network eutectic, which reduced the joint's heat resistance and thus lowered the joint's shear strength.

[0089] Comparative Example 2

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

[0091] Step 1): Process the weldable portions of both the first and second base materials to a surface roughness of Ra0.4; then clean the oil stains on the weldable portions with anhydrous ethanol; fix the weldable areas using spot welding, controlling the weld gap to 0.07mm; then uniformly mix powdered solder and Nicorobraz s-binder adhesive at a mass ratio of 90%:10% to obtain solder paste; then apply the solder paste to an area within 2mm of the weldable area (the designated area); the amount of paste applied is 4 times the volume of the weldable area.

[0092] Nicorobraz White stop-off TYPE II flow inhibitor was applied to the non-welding parts of the first and second base materials. The distance between the application position and the farthest part of the intermediate layer solder did not exceed 1.6 mm, and the flow inhibitor did not contact the intermediate layer alloy solder, thus obtaining the part to be welded.

[0093] The first and second base materials are both additive high-temperature alloy parts prepared by selective laser melting process; the chemical composition of the first and second base materials is: Cr 8%, Co 8%, W 8%, Mo 2.2%, Al 5.7%, Ti 1%, Ta 5.5%, C 0.05%, B 0.015%, Ni balance;

[0094] The chemical composition of the intermediate layer solder by weight percentage is: Cr 14%, W 7%, B 2.7%, Hf 1.5%, Zr 1.5%, Ni balance; the particle size of the powdered solder is not greater than 100μm; the powdered solder is prepared by gas atomization process; the parameters of the gas atomization process are: melting temperature 1550℃; powder spraying temperature 1520℃; atomizing gas is argon; atomization pressure is 8MPa.

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

[0096] The microstructure of the joint of the additively manufactured high-temperature alloy component obtained in this comparative example is analyzed as follows: Figure 3 As shown, there is no non-isothermal solidification structure in the weld zone, but solid-state cracks appeared in the diffusion-affected zone of the base metal. Furthermore, the resulting additively manufactured high-temperature alloy component exhibits a shear strength of 165 MPa at 980°C. In this comparative example, the annealing time was only 20 minutes, which failed to sufficiently eliminate the residual stress in the base metal. During the subsequent joining process, the further interaction between the solder and base metal elements exacerbated the stress state, leading to solid-state cracks in the diffusion-affected zone of the base metal, thus affecting the shear strength of the joint.

[0097] Comparative Example 3

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

[0099] Step 1): Process the weldable portions of both the first and second base materials to a surface roughness of Ra0.4; then clean the oil stains on the weldable portions with anhydrous ethanol; fix the weldable areas using spot welding, controlling the weld gap to 0.07mm; then uniformly mix powdered solder and Nicorobraz s-binder adhesive at a mass ratio of 90%:10% to obtain solder paste; then apply the solder paste to an area within 2mm of the weldable area (the designated area); the amount of paste applied is 4 times the volume of the weldable area.

[0100] Nicrobraz White stop-off TYPE II flux is applied to the non-welding part of the first base material and the second base material, the distance between the application position and the farthest position of the intermediate layer solder is not more than 1.6 mm, and the flux does not contact the intermediate layer alloy solder, and the welding part is obtained;

[0101] The first base material and the second base material are both additive high-temperature alloy parts prepared by a laser selective melting process; the chemical composition of the first base material and the second base material is: Cr 8%, Co 8%, W 8%, Mo 2.2%, Al 5.7%, Ti 1%, Ta 5.5%, C 0.05%, B 0.015%, and Ni balance;

[0102] The chemical composition of the intermediate layer solder is: Cr 14%, W 7%, B 4.1%, and Ni balance by weight percentage; the particle size of the powdered solder is not greater than 100 μm; the powdered solder is prepared by a gas atomization process; the parameters of the gas atomization process are: a smelting temperature of 1550 ℃; a powder spraying temperature of 1520 ℃; an atomizing gas of argon; and an atomizing pressure of 8 MPa.

[0103] Step 2): the welding part is placed in a drying box for drying treatment, the temperature of the drying treatment is 100 ℃, and the time of the drying treatment is 1 h; then the welding part is placed in a vacuum brazing furnace for annealing treatment and connecting treatment in sequence, and then the welding part is cooled to 80 ℃ in the furnace and taken out, to obtain an additive manufacturing high-temperature alloy component; the temperature of the annealing treatment is 1030 ℃; the time of the annealing treatment is 220 min; the temperature of the connecting treatment is 1160 ℃; the time of the connecting treatment is 240 min; and the atmosphere in the furnace is vacuum or argon.

[0104] The joint of the additive manufacturing high-temperature alloy component obtained in the present comparative example is analyzed, and the non-isothermal solidification structure does not exist in the weld zone, but 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 is insufficient, and the shear strength of the additive manufacturing high-temperature alloy component obtained at 980 ℃ is 173 MPa.

[0105] From the above Examples 1-3, it can be seen that the additive manufacturing high-temperature alloy is successfully implemented by the transient liquid phase connection, the joint has no non-isothermal solidification structure, and the shear strength of the joint at 980 ℃ is not less than 300 MPa, which shows that the transient liquid phase connection method of the present application can realize high-performance connection of the additive manufacturing high-temperature alloy.

[0106] It can be seen from the above Comparative Examples 1-3 that the shear strength of the joints at 980℃ is less than 300MPa, the non-isothermal solidification structure existing in the weld zone of Comparative Example 1 affects the joint performance, the solid-state crack in the diffusion affected zone of the base metal of the joint of Comparative Example 2 affects the joint performance, and the intrinsic strength of the weld base metal of Comparative Example 3 is insufficient, which affects the overall performance of the joint. This shows that 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, the high-performance transient liquid phase connection of the superalloy by additive manufacturing cannot be successfully achieved.

[0107] It is easily understood by those skilled in the art that the advantageous technical features of the above-mentioned modes can be freely combined and superimposed without conflict.

[0108] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of transient liquid phase bonding of an additively manufactured superalloy piece, the method comprising: The welding method comprises the following steps: Step 1): adding an intermediate layer solder to a to-be-welded area to obtain a to-be-welded piece; wherein the to-be-welded area is formed by oppositely spacing a to-be-welded part of a first base material and a to-be-welded part of a second base material; Wherein, the first base material and the second base material are both additive high-temperature alloy pieces; the chemical composition of the first base material is, in terms of 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; the chemical composition of the second base material is, in terms of 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; the to-be-welded gap is less than or equal to 0.08mm; Step 2): performing transient liquid phase bonding treatment on the to-be-welded piece to connect the first base material, the intermediate layer solder and the second base material together; Wherein, the chemical composition of the intermediate layer solder is, in terms of weight percentage: Cr 11%-17%, W 5%-9%, B 1%-3.5%, Hf 0.3%-3%, Zr 0.3%-3%, Ni balance; Wherein, the transient liquid phase bonding treatment comprises annealing treatment and connection treatment performed in sequence; the temperature of the annealing treatment is 1020-1040℃; the time of the annealing treatment is 60-240min; the temperature of the connection treatment is 1120-1200℃; the time of the connection treatment is 100-360min.

2. The method of claim 1, wherein the method of transient liquid phase bonding of an additively manufactured superalloy component is characterized by, The intermediate layer solder is a foil strip solder; The thickness of the foil strip solder is 0.02-0.06mm.

3. The method of claim 2, wherein the transient liquid phase bonding of the additively manufactured superalloy component is performed at a temperature of from about 1000 °C to about 1200 °C. The step of adding the intermediate layer solder to the to-be-welded area comprises: placing the foil strip solder inside the to-be-welded area; further comprising: spot welding the foil strip solder in a set area; wherein the set area is an area within 2mm from the to-be-welded area; 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 to-be-welded area; and / or The foil strip solder is prepared by a melt quenching process; the parameters of the melt quenching process are: smelting temperature 1390-1590℃; spraying temperature 1410-1510℃; roller surface linear velocity 20-35m / s; distance between nozzle and roller surface 0.2-0.4mm.

4. The method of claim 1, wherein the method of transient liquid phase bonding of additively manufactured superalloy components is characterized by, The intermediate layer solder is a powdery solder; the particle size of the powdery solder is less than or equal to 100μm.

5. The method of claim 4, wherein the additive superalloy article is a turbine vane. The step of adding the intermediate layer solder to the to-be-welded area comprises: mixing the powdery 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 to-be-welded area; the mass ratio of the powdery 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 to-be-welded area; and / or The powdery solder is prepared by using a gas atomization process; and parameters of the gas atomization process are as follows: a smelting temperature is 1390-1590 ℃; a powder spraying temperature is 1410-1570 ℃; an atomizing gas is argon; and an atomizing pressure is 4-10 MPa.

6. The method of claim 1, wherein the method of transient liquid phase bonding of additively manufactured superalloy components further comprises: The additively manufactured high-temperature alloy part is prepared by using a laser selective melting process or a laser melting deposition process.

7. The method of claim 1, wherein the method of transient liquid phase bonding of additively manufactured superalloy components further comprises: In the step 1), the surface roughness of the to-be-welded part of the first base material is Ra0.2-Ra0.8; and / or The surface roughness of the to-be-welded part of the second base material is Ra0.2-Ra0.

8. And / or After the step of adding the intermediate layer solder to the to-be-welded area, the method further comprises: applying a flow-resistant agent to non-to-be-welded parts of the first base material and the second base material; The flow-resistant agent is not in contact with the intermediate layer solder, and the distance between the application position of the flow-resistant agent and the intermediate layer solder is less than or equal to 2 mm.

8. The method of claim 1, wherein the method of transient liquid phase bonding of additively manufactured superalloy components further comprises: In the step 2), the transient liquid phase connection treatment is performed by using a vacuum heat treatment furnace or a vacuum brazing furnace; The atmosphere in the furnace is vacuum or argon; and / or Before the step of the transient liquid phase connection treatment, the method further comprises: performing a drying treatment on the to-be-connected parts; the temperature of the drying treatment is 90-120 ℃; and the time of the drying treatment is 40-60 min; and / or After the step of the transient liquid phase connection treatment, the method further comprises: a cooling treatment; and the cooling treatment is performed by using a furnace cooling method.

9. An additively manufactured high temperature alloy component, characterized by, The additively manufactured high-temperature alloy component is a welded part obtained by using the transient liquid phase connection method according to any one of claims 1-8; No non-isothermal solidification structure is observed at the weld of the additively manufactured high-temperature alloy component; the microstructure at the weld comprises γ phase and γ' phase; the γ' phase is uniformly and dispersedly distributed at the weld; the γ' phase is in a near-cubic shape, and the volume fraction of the γ' phase is 45-55%; and / or The shear strength of the additively manufactured high-temperature alloy component at 980 ℃ is greater than or equal to 320 MPa.

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