Filling wire for double-wire electric arc additive manufacturing of TaNbTiZrY refractory high-entropy alloy and process method

Abstract

The invention discloses a filling wire for double-wire electric arc additive manufacturing of TaNbTiZrY refractory high-entropy alloy and a process method, and belongs to the technical field of additive manufacturing. The TaNbTiZrY refractory high-entropy alloy is manufactured through electric arc additive manufacturing of the cable type filling wire and the solid filling wire. The cable type filling wire is formed by twisting seven filling wires with the diameter of 0.6 mm, wherein the seven filling wires comprise three Nb wires, three Ti-Y alloy wires and one pure Zr wire, and the Ti-Y alloy wires comprise 97.5-99.5 wt.% of Ti, 0.5-2.5 wt.% of Y and one pure Zr wire. A pure Zr wire is used as a central wire, other six filling wires with the same components are arranged at intervals in a crossed mode on the periphery, the twisting speed is 4 m / s, and the lay length is set to be 10 mm. And the solid filling wire is a pure Ta wire with the diameter of 1.2 mm. The TA1 is used as a substrate, and high-efficiency, high-quality and low-cost preparation of the TaNbTiZrY refractory high-entropy alloy can be achieved by controlling parameters such as the wire feeding speed, the welding current and the interlayer cooling time.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of additive manufacturing, and particularly relates to a filling wire and process method for double-wire electric arc additive manufacturing of TaNbTiZrY refractory high-entropy alloy. BACKGROUND

[0002] High-entropy alloy generally refers to an alloy system containing five or more than five main alloying elements, and the atomic percentage of each main element is between 5% and 35%. Refractory high-entropy alloy generally contains at least two refractory metal elements. Its unique multi-main element synergistic effect endows the material with excellent high-temperature strength, radiation resistance and thermal shock resistance, etc., and shows great application potential in high-end fields such as aerospace, energy and electronics. However, the high melting point of refractory high-entropy alloy poses many challenges to traditional processing methods. During casting, the high melting point leads to high energy consumption and short mold life; during forging and machining, work hardening makes the material difficult to deform, and the processing cost is high and the precision is difficult to guarantee, which limits the wide application of refractory high-entropy alloy.

[0003] Additive manufacturing technology, with its unique way of layer-by-layer accumulation of materials, breaks through the limitations of traditional processing technology, providing an efficient and flexible solution for the manufacturing of complex structural parts, and has attracted much attention in the field of refractory high-entropy alloy processing. Among them, electric arc additive manufacturing uses electric arc as a heat source to melt metal wire, and realizes the layer-by-layer accumulation of materials by precisely controlling the wire feeding speed and the moving path of the electric arc. Compared with other additive manufacturing technologies, electric arc additive manufacturing has lower equipment cost and higher deposition rate, and is suitable for manufacturing large parts.

[0004] In additive manufacturing, wire materials have significant advantages over powder raw materials: lower preparation and storage cost, lower equipment requirement, no need for explosion-proof measures and no dust health risk; material utilization rate is as high as more than 95%, powder bed technology needs to spread powder and recycle un-melted powder, and the actual utilization rate is usually less than 70%. In addition, during sintering or melting of powder materials, the bonding between powder particles is complex, and problems such as porosity and uneven density may occur. In the melting and deposition process of wire materials, the flow and accumulation form can be more easily controlled, and better forming precision and quality can be obtained.

[0005] The electric arc heat source is generated by the ionization of gas between the electrode and the workpiece, and the energy distribution is in a "Gaussian-exponential" mixed mode, with a central heat flux density lower than that of laser and electron beam, but an action diameter significantly larger than that of the latter two. This "low peak, wide scope" energy input characteristic can avoid the evaporation loss of low-melting-point element Y due to local overheating under high-temperature instantaneous heating; in addition, the large volume of electric arc molten pool allows the liquid metal to stay in the molten pool for a longer time, which is conducive to the full diffusion and mixing of elements such as Ta, Nb, Ti, Zr and Y, reduces composition segregation, and ensures the uniformity of high-entropy alloy composition.

[0006] Through the search of the existing refractory high-entropy alloy additive manufacturing technology, it is found that there is no precedent for preparing refractory high-entropy alloy by arc additive manufacturing technology. Patent (Patent No. 202411350489.5) discloses a method and application of electron beam three-wire in-situ additive manufacturing of TiZrNbHfTa refractory high-entropy alloy. The method includes the following steps: firstly, three-dimensional modeling of the target component is carried out, and slicing processing is carried out; then, three-wire printing is adopted, the relative position relationship of the three wires, the angle and distance between the three wires and the substrate are set, the wire feeding speed is set, and the electron beam scanning mode is set; finally, 3D printing is carried out. The method realizes flexible regulation and control of alloy composition and integrated forming of refractory high-entropy alloy. The shortcomings of the method are that the electron beam additive manufacturing has strict requirements on equipment and environment, the cost is high, the control of three-wire synchronous wire feeding is difficult, and only tensile data at 450℃ is provided, without verification of mechanical properties at higher temperatures (such as 800-1200℃).

[0007] Patent (Patent No. 202410785494.2) discloses a method for preparing refractory high-entropy alloy by laser deposition combined with laser remelting technology. The method melts the mixed refractory element powder mixture with high melting point by using laser deposition combined with laser remelting technology, so as to obtain refractory high-entropy alloy. The limitations of the method are that the production cycle is significantly prolonged and the deposition efficiency is low because the mixed refractory element powder mixture needs to be remelted once for each deposition layer, especially for large-size components. Therefore, it is a technical problem in the field to develop a filler wire and process method for arc additive manufacturing of refractory high-entropy alloy, so as to realize high-quality, low-cost and large-size preparation of refractory high-entropy alloy. SUMMARY

[0008] The present application aims to provide a filler wire and process method for double-wire arc additive manufacturing of TaNbTiZrY refractory high-entropy alloy. The composition of the additive manufactured refractory high-entropy alloy is about Ta: 37.2%, Nb: 27.7%, Ti: 27.6%-27.9%, Zr: 7.1%, and Y: 0.1%-0.4%. The use of cable filler wire and solid filler wire respectively and the arc additive manufacturing process of TaNbTiZrY refractory high-entropy alloy can efficiently, high-quality and low-cost manufacture refractory high-entropy alloy.

[0009] The technical solution of the present application is a filler wire and process method for double-wire arc additive manufacturing of TaNbTiZrY refractory high-entropy alloy, which includes double-wire arc additive manufacturing of TaNbTiZrY refractory high-entropy alloy special cable filler wire and solid filler wire, and double-wire arc additive manufacturing process of TaNbTiZrY refractory high-entropy alloy.

[0010] The first technical solution adopted by the present application is a filling wire for double-wire electric arc additive manufacturing of TaNbTiZrY refractory high-entropy alloy, characterized in that it comprises a cable type filling wire and a solid filling wire; the cable type filling wire has a diameter of 1.8 mm and is twisted by 7 filling wires each having a diameter of 0.6 mm, which are 3 Nb wires, 3 Ti-Y alloy wires and 1 pure Zr wire, wherein the Ti-Y alloy wire has a composition of Ti: 97.5-99.5 wt.%, Y: 0.5-2.5 wt.%; the pure Zr wire is the center wire, and the other 6 wires are distributed around the center wire, and the wires of the same material in the other 6 wires are cross-distributed at intervals, and the twisting parameters are set as: twisting speed 4 m / s, and twist pitch 10 mm. The solid filling wire is a pure Ta wire, and the diameter of the solid filling wire is 1.2 mm.

[0011] The second technical solution adopted by the present application is a process method for double-wire electric arc additive manufacturing of TaNbTiZrY refractory high-entropy alloy, and the equipment used includes a workbench, a welding mechanism, a wire feeding mechanism, a control mechanism and a protective gas mechanism; the workbench is used to fix the substrate and can move in the horizontal plane composed of X-axis / Y-axis, and the X-axis is the welding progress direction; the welding mechanism is composed of a welding machine and a welding gun, the welding gun can move in the vertical direction (z-axis), and tungsten argon arc welding is adopted; the wire feeding mechanism is composed of a wire feeding pipe and a wire feeding machine, and two wire feeding mechanisms are adopted; the wire feeding pipe can move together with the welding gun in the Z-axis direction, the end of the wire feeding pipe is opposite to the bottom of the tungsten electrode of the welding gun, and the two wire feeding pipes are symmetrically distributed relative to the plane formed by the X-axis and the Z-axis, one wire feeding pipe corresponds to the cable type filling wire, and the other wire feeding pipe corresponds to the solid filling wire; the control mechanism is used to control the movement of the workbench, and the input program can realize fixed trajectory additive manufacturing; the protective gas mechanism is composed of an argon tank and a gas injection pipeline, and is used for welding air isolation.

[0012] Use TA1 as substrate, first polishing the substrate, removing contaminants and oxide layer, using alcohol to clean the surface of the substrate, after the alcohol evaporates, fix the substrate to the workbench, put two different filling wires into two wire feeders respectively, the wire feeding speed is 1.3 m / min; turn on the welding machine, set the welding current, the initial welding current, then start the four-layer additive, reduce the current by 10A, the fifth layer and the subsequent layers maintain the current corresponding to the fourth layer; input the additive motion path program into the control mechanism, the interlayer cooling time is 30-50s, set the motion speed of the workbench to 80mm / min, and move the tungsten electrode at the bottom of the welding gun to a distance of 3-5mm from the substrate; open the argon cylinder, observe whether the protective gas is sprayed at the welding gun, determine that all parameter settings are complete, and prepare for starting, start preheating after the preheating is completed, start printing, after the first layer of additive is completed, reduce the welding current by 10A, and carry out the second layer of additive. After the second layer of additive is completed, reduce the welding current by 10A, and carry out the third layer of additive, repeat the above operation until the fourth layer of additive is completed, the welding current of the fifth layer of additive is the same as that of the fourth time, and does not change any more, until all layers of additive manufacturing are completed; after the printing is cooled, the substrate is taken out, and the TaNbTiZrY refractory high-entropy alloy material part can be obtained after cutting.

[0013] The wire feeding pipe is symmetrically distributed relative to the plane where the XZ axis is located, and the angle between the wire feeding pipe and the plane where the XZ axis is located is 20-30 degrees, and the angle between the wire feeding pipe and the plane where the XY axis is located is 15-25 degrees.

[0014] The wire feeding speed is 1-1.5 m / min, the welding current in the whole process is 220A-270A, the motion speed of the workbench is 80mm / min, the protective gas flow is set to 12-15L / min, and the interlayer cooling time is 30-50s.

[0015] The composition of the finally manufactured refractory high-entropy alloy is about Ta: 37.2%, Nb: 27.7%, Ti: 27.6%-27.9%, Zr: 7.1%, and Y: 0.1%-0.4%.

[0016] In the additive manufacturing TaNbTiZrY refractory alloy, the addition of Zr reduces the liquidus temperature of the alloy. In the rapid solidification process, the reduction of the liquidus temperature means the reduction of the undercooling degree of the alloy during solidification. The undercooling composition is an important driving force for dendrite growth, and the reduction of the undercooling degree inhibits the growth of dendrites, so that the dendrite size is refined. Y reacts with free oxygen in the molten pool to generate nano-sized Y2O3 particles, which are dispersedly distributed in the grain boundary and matrix, hinder the sliding and climbing of dislocations in the alloy, and improve the comprehensive mechanical properties at room temperature and high temperature. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The cross section of the cable type filling wire

[0018] Figure 2A model diagram for additive manufacturing of a refractory high-entropy alloy of TaNbTiZrY by double wire electric arc; DETAILED DESCRIPTION

[0019] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0020] Embodiment 1

[0021] This embodiment uses a cable filling wire and a pure Ta wire for additive manufacturing, the cable filling wire has a diameter of 1.8 mm and is twisted by 7 filling wires each having a diameter of 0.6 mm, which are 3 Nb wires, 3 Ti-Y alloy wires, wherein Ti: 97.5 wt.%, Y: 2.5 wt.%, and 1 Zr wire. The pure Zr wire is used as a center wire, and the other 6 filling wires are in the periphery, and the same metal is in the same position, and the twisting parameter is set as: the twisting speed is 4 m / s, and the twist pitch is set as 10 mm. The solid filling wire is a pure Ta wire, and the alloy wire has a diameter of 1.2 mm.

[0022] TA1 plate is used as a substrate, and the surface of the substrate is polished to remove dirt and oxide layer using an angle grinder, and then the surface of the substrate is cleaned using alcohol. After waiting for the alcohol to evaporate, the substrate is fixed to the workbench. The above-mentioned cable filling wire (Nb-(Ti-Y)-Zr) and pure tantalum wire are respectively put into two wire feeders, both of which adopt oscillating wire feeding, the wire feeding pipe is 20-30 degrees to the plane where the XZ axis is located, 15-25 degrees to the plane where the XY axis is located, and symmetrically distributed relative to the plane where the XZ axis is located, and the wire feeding speed is 1.3 m / min. Turn on the welding machine and set the welding current to 270 A. Input the additive motion path program into the control system, set the workbench motion speed to 80 mm / min, the interlayer cooling time to 40 s, and move the bottom of the welding torch tungsten electrode to a distance of 3-5 mm from the substrate. Open the argon cylinder and set the gas flow to 15 L / min. Observe whether the protective gas is ejected at the welding torch. Run the program and start preheating. After preheating, keep the welding current at 270 A unchanged, continue to print the first layer, after the first layer of additive manufacturing is completed, reduce the welding current by 10 A to 260 A, print the second layer, after the second layer of additive manufacturing is completed, reduce the welding current by 10 A to 250 A, print the third layer, after the third layer of additive manufacturing is completed, reduce the welding current by 10 A to 240 A, print the fourth layer, after the fourth layer of additive manufacturing is completed, the fifth layer welding current is the same as the fourth time, and the welding current is kept at 240 A without changing, until 50 layers of printing are completed. After waiting for the printed part to cool down, take out the substrate, and after cutting, the TaNbTiZrY refractory high-entropy alloy material part can be obtained.

[0023] No obvious pores and cracks were observed in the refractory TaNbTiZrY high-entropy alloy part obtained in Example 1. Tensile tests and microhardness tests were performed on the part sample at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 903 MPa, and the elongation at break is 1.5%. The tensile strength at 1000°C reaches 528 MPa, and the elongation at break is 2.2%, and the microhardness is 308 HV.

[0024] Example 2

[0025] This example uses a cable filler wire and pure Ta wire for additive manufacturing. The cable filler wire has a diameter of 1.8 mm and is twisted from 7 filler wires each with a diameter of 0.6 mm, including 3 Nb wires, 3 Ti-Y alloy wires, and 1 Zr wire. The pure Zr wire is used as the center wire, and the other 6 filler wires are arranged in the periphery. The same metal is in the same position, and the twisting parameters are set as follows: twisting speed 4 m / s, and twist pitch 10 mm. The solid filler wire is a pure Ta wire, and the alloy wire has a diameter of 1.2 mm.

[0026] TA1 plate is used as the substrate, and the surface of the substrate is polished to remove dirt and oxide layer using an angle grinder. Then the substrate surface is cleaned with alcohol. After waiting for the alcohol to evaporate, the substrate is fixed to the workbench. The above-mentioned cable filler wire (Nb-(Ti-Y)-Zr) and pure tantalum wire are respectively placed in two wire feeders, both of which use oscillating wire feeding. The wire feeding pipe is 20-30 degrees to the plane of the XZ axis and 15-25 degrees to the plane of the XY axis, and is symmetrically distributed relative to the plane of the XZ axis. The wire feeding speed is 1.3 m / min. Turn on the welding machine and set the initial welding current to 270 A. Input the additive motion path program into the control system, set the workbench motion speed to 80 mm / min, the interlayer cooling time to 40 s, and move the welding torch tungsten bottom to a distance of 3-5 mm from the substrate. Open the argon cylinder and set the gas flow to 15 L / min. Observe whether the protective gas is ejected at the welding torch. Run the program and start preheating. After preheating, keep the welding current unchanged and continue printing the first layer. After the first layer of additive manufacturing is completed, reduce the welding current by 10 A and print the second layer. Repeat the above operation of reducing the current by 10 A layer by layer until the fourth layer of additive manufacturing is completed. The welding current of the fifth layer is the same as that of the fourth time, and it is not changed any more until the 50-layer printing is completed. After the printing is cooled, the substrate is removed, and the TaNbTiZrY refractory high-entropy alloy material part can be obtained after cutting.

[0027] No obvious pores and cracks were observed in the refractory TaNbTiZrY high-entropy alloy part obtained in Example 2. Tensile tests and microhardness tests were performed on the part sample at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 1172 MPa, and the elongation at break is 2.4%. The tensile strength at 1000°C reaches 702 MPa, and the elongation at break is 3.0%, and the microhardness is 401 HV.

[0028] Example 3

[0029] This example uses a cable filler wire and a pure Ta wire for additive manufacturing. The cable filler wire has a diameter of 1.8 mm and is twisted from 7 filler wires each having a diameter of 0.6 mm, including 3 Nb wires, 3 Ti-Y alloy wires each having a Ti content of 99.5 wt.% and a Y content of 0.5 wt.%, and 1 Zr wire. The pure Zr wire is used as a center wire, and the other 6 filler wires are arranged in the periphery. The same metal is arranged in the same position, and the twisting parameters are set as follows: twisting speed 4 m / s, and twist pitch 10 mm. The solid filler wire is a pure Ta wire, and the alloy wire has a diameter of 1.2 mm.

[0030] TA1 plate is used as a substrate, and the surface of the substrate is polished to remove dirt and oxide layer using an angle grinder. Then the substrate surface is cleaned with alcohol. After waiting for the alcohol to evaporate, the substrate is fixed to the workbench. The above-mentioned cable filler wire (Nb-(Ti-Y)-Zr) and pure tantalum wire are respectively placed in two wire feeders, both of which use oscillating wire feeding. The wire feeding pipe is 20-30 degrees to the plane of the XZ axis and 15-25 degrees to the plane of the XY axis, and is symmetrically distributed relative to the plane of the XZ axis. The wire feeding speed is 1.3 m / min. Turn on the welding machine and set the welding current to 270 A. Input the additive motion path program into the control system, set the workbench motion speed to 80 mm / min, the interlayer cooling time to 40 s, and move the bottom of the welding gun tungsten electrode to a distance of 3-5 mm from the substrate. Open the argon cylinder and set the gas flow to 15 L / min. Observe whether the protective gas is ejected from the welding gun. Run the program and start preheating. After preheating, keep the welding current unchanged and continue printing the first layer. After the first layer of additive manufacturing is completed, reduce the welding current by 10 A and print the second layer. Repeat the above operation until the fourth layer of additive manufacturing is completed. The welding current of the fifth layer is the same as that of the fourth time, and is not changed until the 50-layer printing is completed. After the printing is cooled, the substrate is removed, and the TaNbTiZrY refractory high-entropy alloy material part can be obtained after cutting.

[0031] The refractory TaNbTiZrY high-entropy alloy part obtained in Example 3 has good formability, and no obvious pores and cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 962 MPa, and the elongation at break is 1.9%. The tensile strength at 1000°C reaches 571 MPa, and the elongation at break is 2.5%, and the microhardness is 316 HV.

[0032] Example 4

[0033] On the basis of Example 2, the cooling time is changed to 30 s, and other components and process parameters are consistent with those of Example 2.

[0034] The refractory TaNbTiZrY high-entropy alloy part obtained in Example 4 has good formability, and no obvious pores and cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 1084 MPa, and the elongation at break is 2.2%. The tensile strength at 1000°C reaches 659 MPa, and the elongation at break is 2.7%, and the microhardness is 368 HV.

[0035] Example 5

[0036] On the basis of Example 2, the cooling time is changed to 50 s, and other components and process parameters are consistent with those of Example 2.

[0037] The refractory TaNbTiZrY high-entropy alloy part obtained in Example 5 has good formability, and no obvious pores and cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 1206 MPa, and the elongation at break is 2.6%. The tensile strength at 1000°C reaches 743 MPa, and the elongation at break is 3.0%, and the microhardness is 419 HV.

[0038] Example 6

[0039] On the basis of Example 2, the welding current is changed to 250 A, and the cooling time is changed to 30 s, and other components and process parameters are consistent with those of Example 2.

[0040] The refractory TaNbTiZrY high-entropy alloy part obtained in Example 6 has good formability, and no obvious pores and cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 1109 MPa, and the elongation at break is 2.2%. The tensile strength at 1000°C reaches 676 MPa, and the elongation at break is 2.8%, and the microhardness is 385 HV.

[0041] Example 7

[0042] On the basis of example 2, the welding current is changed to 250 A, and other components and process parameters are consistent with example 2.

[0043] The refractory TaNbTiZrY high-entropy alloy part obtained in example 7 has good formability, and no obvious pores and cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000℃, respectively. The results show that the tensile strength at room temperature reaches 1256 MPa, and the elongation at break is 2.6%. The tensile strength at 1000℃ reaches 774 MPa, and the elongation at break is 3.2%, and the microhardness is 436 HV.

[0044] Example 8

[0045] On the basis of example 2, the welding current is changed to 250 A, and other components and process parameters are consistent with example 2.

[0046] The refractory TaNbTiZrY high-entropy alloy part obtained in example 8 has good formability, and no obvious pores and cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000℃, respectively. The results show that the tensile strength at room temperature reaches 1025 MPa, and the elongation at break is 2.1%. The tensile strength at 1000℃ reaches 613 MPa, and the elongation at break is 2.7%, and the microhardness is 349 HV.

[0047] Example 9

[0048] On the basis of example 2, the welding current is changed to 220 A, and other components and process parameters are consistent with example 2.

[0049] The refractory TaNbTiZrY high-entropy alloy part obtained in example 9 has good formability, and no obvious pores and cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000℃, respectively. The results show that the tensile strength at room temperature reaches 876 MPa, and the elongation at break is 1.7%. The tensile strength at 1000℃ reaches 517 MPa, and the elongation at break is 2.3%, and the microhardness is 299 HV.

[0050] Example 10

[0051] On the basis of example 2, the welding current is changed to 220 A, and other components and process parameters are consistent with example 2.

[0052] The refractory TaNbTiZrY high-entropy alloy part obtained in Example 11 has good formability, and no obvious pores and cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 823 MPa, and the elongation at break is 1.6%. The tensile strength at 1000°C reaches 458 MPa, and the elongation at break is 2.1%, and the microhardness is 259 HV.

[0053] Example 11

[0054] On the basis of Example 2, the welding current is changed to 220 A, and the cooling time is 50 s. The other components and process parameters are consistent with those of Example 2.

[0055] The refractory TaNbTiZrY high-entropy alloy part obtained in Example 11 has good formability, and no obvious pores and cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 823 MPa, and the elongation at break is 1.6%. The tensile strength at 1000°C reaches 458 MPa, and the elongation at break is 2.1%, and the microhardness is 259 HV.

[0056] Comparative Example 1

[0057] On the basis of Example 2, the Ti-Y alloy wire component is changed, Ti: 97 wt.%, Y: 3 wt.%, and the other components and process parameters are consistent with those of Example 2.

[0058] The refractory TaNbTiZrY high-entropy alloy part obtained in Comparative Example 1 has a small amount of pores on the surface, and no cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 506 MPa, and the elongation at break is 1.0%. The tensile strength at 1000°C reaches 282 MPa, and the elongation at break is 1.4%, and the microhardness is 256 HV.

[0059] Comparative Example 2

[0060] On the basis of Example 2, the Ti-Y alloy wire component is changed, Ti: 99.8 wt.%, Y: 0.2 wt.%, and the other components and process parameters are consistent with those of Example 2.

[0061] The refractory TaNbTiZrY high-entropy alloy part obtained in Comparative Example 2 has a small amount of pores on the surface, and no cracks are observed. The part sample is subjected to tensile test and microhardness test at room temperature and 1000°C, respectively. The results show that the tensile strength at room temperature reaches 649 MPa, and the elongation at break is 1.3%. The tensile strength at 1000°C reaches 391 MPa, and the elongation at break is 1.6%, and the microhardness is 227 HV.

[0062] Comparative Example 3

[0063] On the basis of Example 2, the welding current is changed to 300 A, and other components and process parameters are consistent with Example 2.

[0064] The refractory TaNbTiZrY high-entropy alloy part obtained in Comparative Example 3 has a small amount of pores on the surface, and no cracks are observed. The tensile test and microhardness test are carried out at room temperature and 1000℃, respectively. The results show that the tensile strength reaches 515 MPa at room temperature, and the elongation at break is 1.3%. The tensile strength reaches 326 MPa at 1000℃, and the elongation at break is 1.7%, and the microhardness is 368 HV.

[0065] Comparative Example 4

[0066] On the basis of Example 2, the welding current is changed to 190 A, and other components and process parameters are consistent with Example 2.

[0067] The refractory TaNbTiZrY high-entropy alloy part obtained in Comparative Example 4 has a small amount of pores on the surface, and no cracks are observed. The tensile test and microhardness test are carried out at room temperature and 1000℃, respectively. The results show that the tensile strength reaches 536 MPa at room temperature, and the elongation at break is 1.1%. The tensile strength reaches 312 MPa at 1000℃, and the elongation at break is 1.5%, and the microhardness is 216 HV.

[0068] By adding Y within a reasonable range, it reacts with free oxygen in the molten pool to form nanoscale Y2O3 particles, which are dispersed in the grain boundaries and matrix, hindering the sliding and climbing of dislocations in the alloy, suppressing the high-temperature creep deformation of the alloy, and improving the comprehensive mechanical properties. In addition, it can also purify the grain boundaries and reduce the risk of grain boundary brittleness, further improving the plasticity of the alloy. When the Y content is too low, the strengthening effect is not obvious; when the Y content is too high, due to the large atomic radius of rare earth Y, there is a significant size difference with other elements in the alloy, which is easy to form brittle intermetallic compounds such as Y-Ti and Y-Zr phases. These compounds are usually distributed in the grain boundaries or interdendritic regions, becoming the preferred path for crack initiation and propagation, resulting in a significant decrease in tensile strength and elongation of the alloy.

[0069] When the current is too low, the insufficient line energy density will cause the wire material not to be fully fused, forming pores, unfused defects and composition segregation. Unfused defects will significantly reduce the density of the material, become a stress concentration source and accelerate crack propagation, thereby deteriorating the tensile strength and elongation. At the same time, too low energy input may inhibit the full flow of the molten pool, resulting in uneven grain size, weakening the effects of fine-grain strengthening and dislocation pinning. The decrease in microhardness is related to the low density of the unfused area.

[0070] Table 1 Process equipment used in the examples

[0071] Equipment name Model Selling factory or source TIG welder Precision Tig 375 Lincoln Electric Filling machine WF-007A Jinan Welda Machinery Co., Ltd. Programmable motion controller BE-2017 Variable Energy Technology Co., Ltd. Slide rail GX150 East Tai City Oulai Transmission Component Co., Ltd.

[0072] Table 2 Parameters and characterization results of each example

[0073] Filling wire composition (Ti-Y) / wt.% Welding current / A Interlayer cooling time / S Room temperature tensile strength / Mpa Room temperature elongation at break / % 1000 °C tensile strength / Mpa 1000 °C elongation at break / % Microhardness / HV Example 1 Ti: 97.5 Y: 2.5 270 40 903 1.5 528 2.2 308 Example 2 Ti: 98.5 Y: 1.5 270 40 1172 2.4 702 3.0 401 Example 3 Ti: 99.5 Y: 0.5 270 40 962 1.9 571 2.5 316 Example 4 Ti: 98.5 Y: 1.5 270 30 1084 2.2 659 2.7 368 Example 5 Ti: 98.5 Y: 1.5 270 50 1206 2.6 743 3.0 419 Example 6 Ti: 98.5 Y: 1.5 250 30 1109 2.2 676 2.8 385 Example 7 Ti: 98.5 Y: 1.5 250 40 1256 2.6 774 3.2 436 Example 8 Ti: 98.5 Y: 1.5 250 50 1025 2.1 613 2.7 349 Example 9 Ti: 98.5 Y: 1.5 220 30 876 1.7 517 2.3 299 Example 10 Ti: 98.5 Y: 1.5 220 40 857 1.6 484 2.2 281 Example 11 Ti: 98.5 Y: 1.5 220 50 823 1.6 458 2.1 259 Comparative example 1 Ti: 97 Y: 3 270 40 506 1.0 282 1.4 256 Comparative example 2 Ti: 99.8 Y: 0.2 270 40 649 1.3 391 1.6 227 Comparative example 3 Ti: 98.5 Y: 1.5 300 40 515 1.3 326 1.7 368 Comparative example 4 Ti: 98.5 Y: 1.5 190 40 536 1.1 312 1.5 216

[0074] Excessive current leads to excessive arc energy input, and the molten pool temperature of TaNbTiZrY refractory high-entropy alloy is significantly increased. On the one hand, it causes serious element evaporation, destroys the uniformity of alloy composition, and forms composition segregation and low-melting-point brittle phase; on the other hand, excessive heat input prolongs the cooling time of the molten pool, promotes grain coarsening, forms coarse columnar crystals, reduces the grain boundary area and increases defects. The tensile strength decreases due to the splitting effect of coarse grains and brittle phase, and the elongation deteriorates due to the reduction of grain boundary defects and plastic phase; although the microhardness may not decrease significantly due to the formation of brittle phase, the overall mechanical property coordination is poor.

[0075] The above examples are only a number of exemplary embodiments embodying the technical solutions of the present application, each embodiment is based on the technical logic extension under the same inventive concept, and the protection scope of the claims is not limited by the above examples. Any person skilled in the art can deduce equivalent embodiments or adaptive adjustments within the technical framework disclosed in the present application by conventional technical means, which are regarded as a reasonable extension of the technical essence of the present application and should be included in the protection scope of the patent right.

Claims

1. A filler wire for dual-wire arc additive manufacturing of TaNbTiZrY refractory high-entropy alloys, characterized in that, It includes cable-type filler wire and solid filler wire; the cable-type filler wire is made of 7 filler wires with a diameter of 0.6 mm, namely 3 Nb wires, 3 Ti-Y alloy wires and 1 pure Zr wire, wherein the composition of the Ti-Y alloy wire is Ti: 97.5~99.5 wt.% and Y: 0.5~2.5 wt.%; with the pure Zr wire as the central wire, the other 6 wires are distributed around it, and the wires of the same material in the other 6 wires are distributed alternately; the solid filler wire is pure Ta wire, and the diameter of the solid filler wire is 1.2 mm.

2. The filler wire for the dual-wire arc additive manufacturing of TaNbTiZrY refractory high-entropy alloys according to claim 1, characterized in that, The stranding parameters for the cable-type filler wire are set as follows: stranding speed 4m / s, and twist pitch 10mm.

3. The additive manufacturing process for TaNbTiZrY refractory high-entropy alloys using filler wire as described in claim 1 or 2, characterized in that, Using TA1 as the substrate, the substrate is first polished to remove contaminants and oxide layers. The substrate surface is then cleaned with alcohol, and after the alcohol evaporates, the substrate is fixed to the worktable. Two different filler wires are placed into two wire feeders respectively. The welding machine is turned on, and the welding current is set. For the first four layers of additive manufacturing, the current is reduced by 10A layer by layer. The current for the fifth layer and subsequent layers is kept at the same level as the fourth layer. The additive manufacturing motion path program is input into the control mechanism. The argon cylinder is turned on, and it is observed whether there is shielding gas ejected from the welding torch. After confirming that all parameters are set and ready, preheating is started. After preheating, printing begins. After the first layer of additive manufacturing is completed, the welding current is reduced by 10A for the second layer. After the second layer is completed, the welding current is reduced by 10A for the third layer. The above operation is repeated until the fourth layer is completed. The welding current for the fifth layer is the same as the fourth layer and is not changed. This process continues until all layers of additive manufacturing are completed. After the printed part cools down, the substrate is removed and cut to obtain a TaNbTiZrY refractory high-entropy alloy part.

4. The method according to claim 3, characterized in that, The wire feeding speed is 1-1.5 m / min, the welding current is 220A-270A throughout the process, the table movement speed is 80 mm / min, the shielding gas flow rate is set to 12-15 L / min, and the interpass cooling time is 30-50 s.

5. The method according to claim 3, characterized in that, The equipment used includes a worktable, welding mechanism, wire feeding mechanism, control mechanism, and shielding gas mechanism. The worktable is used to fix the substrate and can move in the horizontal plane formed by the X-axis and Y-axis, with the X-axis being the welding progress direction. The welding mechanism consists of a welding machine and a welding torch, which can move in the vertical direction (Z-axis) and uses tungsten inert gas (TIG) welding. The wire feeding mechanism consists of a wire feeding tube and a wire feeder, employing two wire feeding mechanisms. The wire feeding tube can move together with the welding torch in the Z-axis direction, with the end of the wire feeding tube facing the bottom of the tungsten electrode of the welding torch. The two wire feeding tubes are symmetrically distributed with respect to the plane containing the X-axis and Z-axis. One wire feeding tube corresponds to cable-type filler wire, and the other corresponds to solid filler wire. The control mechanism is used to control the movement of the worktable, and the input program can realize additive manufacturing with a fixed motion trajectory. The shielding gas mechanism consists of an argon gas cylinder and a gas jet pipeline, used to isolate the welding process from air.

6. The method according to claim 5, characterized in that, The wire feed tube is at an angle of 20 to 30 degrees to the plane containing the XZ axis and at an angle of 15 to 25 degrees to the plane containing the XY axis, and is symmetrically distributed relative to the plane containing the XZ axis; and the bottom of the tungsten electrode of the welding torch is moved to a distance of 3 to 5 mm from the substrate.

7. The method according to claim 3, characterized in that, The final additively manufactured refractory high-entropy alloy has a composition of approximately Ta: 37.2%, Nb: 27.7%, Ti: 27.6%–27.9%, Zr: 7.1%, and Y: 0.1%–0.4%.

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