Preparation method of homogeneous titanium-palladium alloy and application thereof

Abstract

The application discloses a preparation method of a homogeneous titanium-palladium alloy and application of the titanium-palladium alloy, and the preparation method comprises the following steps: putting titanium sponge and palladium gold fragments into a vacuum induction melting furnace in a melt quenching device according to a mass ratio of 96-98:4-2, rapidly melting, and then rapidly quenching into a titanium-palladium intermediate alloy with a thickness of 40-60 microns and a width of 5-10 mm under the protection of argon; crushing the titanium-palladium intermediate alloy into titanium-palladium intermediate alloy fragments with the same particle size as the titanium sponge; taking the titanium sponge and the titanium-palladium intermediate alloy fragments according to a mass ratio of 8-9:2-1, and physically mixing uniformly; pressing the mixture into a billet, namely a titanium-palladium electrode; repeatedly melting the titanium-palladium electrode in a vacuum consumable electrode furnace to obtain a titanium-palladium alloy ingot; and homogenizing annealing the titanium-palladium alloy ingot in a vacuum annealing furnace, so that the titanium-palladium alloy is obtained. The application can accurately control the content and uniformity of the Pd element in the Ti-Pd alloy, and a homogeneous titanium-palladium alloy without segregation and metallurgical defects such as inclusions is prepared.

Description

Technical Field

[0001] This invention belongs to the field of metallic materials technology, and relates to a method for preparing a homogeneous titanium-palladium alloy and its application. Background Technology

[0002] Titanium alloys are alloys formed by adding other alloying elements to titanium. They possess high strength and corrosion resistance, making them a corrosion-resistant structural material. With technological advancements, higher demands are placed on the performance of titanium alloy castings, as well as the uniformity of their composition. Titanium-palladium alloy (Ti-0.2Pd) belongs to the α-titanium alloy family. It not only retains the processing and mechanical properties of industrial pure titanium, as well as its excellent corrosion resistance in oxidizing media, but also exhibits resistance to localized corrosion and crevice corrosion in thermally reducing acidic media, chlorine-saturated brine, moist halogens, and acidic chlorides. Therefore, titanium-palladium alloys are widely used in petroleum, chemical, and medical fields due to their strong corrosion resistance, especially their resistance to crevice corrosion. The Pd content in Ti-0.2Pd titanium alloys is typically 0.1-0.2% by mass. This low Pd content makes it difficult to control the uniformity of palladium distribution, severely affecting its corrosion resistance.

[0003] Chinese Patent CN102051493A describes a method for preparing a homogeneous multi-component titanium alloy. The method involves selecting alloying elements and / or master alloys based on the composition of the alloy. After uniformly mixing the alloying elements and / or master alloys, these are layered with sponge titanium layers in a 5-9 layer arrangement to form a consumable electrode. The prepared electrode is then melted three times in a vacuum consumable electrode furnace and subsequently cooled to obtain the titanium alloy. During the layering process, the combined weight of the first and last layers of sponge titanium accounts for 2 / 3 of the total weight of the sponge titanium. Chinese Patent CN101481759A describes a method for preparing a ruthenium-containing (0.11% wt.) corrosion-resistant titanium alloy. This method involves uniformly mixing ruthenium powder and sponge titanium, pressing them into electrode blocks, then welding these blocks into larger electrodes using a plasma arc welding process, and finally melting the titanium alloy ingot at least twice using a vacuum arc furnace. Chinese patent CN107297485A describes a method for preparing large titanium alloy ingots containing trace elements. A detachable auxiliary support is used to divide the mold cavity into N horizontally arranged compartments (N≥16). Sponge titanium and intermediate alloys are used as raw materials. The materials are weighed and mixed according to the nominal composition of the titanium alloy to be prepared, resulting in N portions of mixed raw materials. N portions of trace element powder are also prepared. Half of each portion of mixed raw material is poured into its corresponding compartment, and then the trace element powder is poured into its corresponding compartment. The remaining half of each portion of mixed raw material is then poured into its corresponding compartment. The auxiliary support is removed from the mold cavity. A short-stroke vertical pressing method is then used to press the mixed raw materials in the mold cavity into large single-weight electrode blocks in one go. Multiple large single-weight electrode blocks are then welded together to form consumable electrodes. These consumable electrodes are then subjected to 2-3 vacuum consumable melting processes to obtain large titanium alloy ingots containing trace elements. In their paper "Preparation Technology and Evaluation Method of High-Homogeneous Titanium Alloy Ingots" published in Foundry Engineering, Han Yunfei et al. demonstrated how high-grade raw materials were used, alloy formulas were adjusted, precise weighing was employed, the compositional fluctuations of the main chemical elements Al, Zr, Mo, and V were controlled, the mixing was uniform, foreign matter contamination was avoided, and melting experience parameters such as current, voltage, and vacuum degree were summarized to optimize the operation method. By using vacuum consumable electrode melting technology, they successfully prepared titanium alloy ingots with small and uniform chemical composition fluctuations.

[0004] It is evident that controlling the uniformity of component distribution is indeed difficult in the preparation of both binary and multi-component titanium alloy castings. Although various methods exist, such as powder mixing, consumable electrode methods, and vacuum melting, the problem of component uniformity remains unresolved. Therefore, this invention employs a special method to obtain an intermediate alloy containing a relatively high amount of trace components, similar in morphology to raw sponge titanium, thereby ensuring the accuracy of palladium element addition and the uniformity of its distribution in the final titanium-palladium alloy. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for preparing a homogeneous titanium-palladium alloy, which can accurately control the content and uniformity of Pd element in the Ti-Pd alloy, thereby obtaining a homogeneous titanium-palladium alloy free from segregation and metallurgical defects.

[0006] Another objective of this invention is to provide an application of a homogeneous titanium-palladium alloy prepared by a method for the preparation of such an alloy in the fields of medical and health care and petrochemicals.

[0007] The technical solution adopted in this invention is a method for preparing a homogeneous titanium-palladium alloy, characterized by comprising the following steps:

[0008] Step 1, Raw material preparation: sponge titanium with a particle size of 100-200 mesh and palladium fragments with a particle size of 100-200 mesh.

[0009] Step 2, Preparation of Titanium-Palladium Master Alloy Strip: Sponge titanium and palladium fragments are rapidly melted (3-10 minutes) in a vacuum induction melting furnace of a melt quenching device at a mass ratio of 96-98:4-2 to prevent the formation of Ti2Pd or TiPd3 phases with inconsistent atomic ratios. This is accompanied by magnetic stirring (3-10 minutes). After melting, the mixture is held for 3-10 minutes, then argon gas is introduced, and the mixture is rapidly quenched under argon protection (argon pressure 0.1-0.5 MPa) to form a titanium-palladium master alloy strip with a thickness of 40-60 micrometers and a width of 5-10 mm. The thin strip of the titanium-palladium master alloy solidifies rapidly under strong stirring, preventing precipitation and segregation, thus ensuring uniform titanium-palladium composition. Furthermore, it is easily broken, preventing the introduction of other impurities during subsequent crushing or pressing, ensuring the overall purity of the alloy.

[0010] Step 3, Titanium-Palladium Master Alloy Fragmentation Treatment: The titanium-palladium master alloy prepared in Step 2 is crushed into titanium-palladium master alloy fragments with the same particle size as sponge titanium.

[0011] Step 4, mixing of sponge titanium and titanium-palladium master alloy: Weigh sponge titanium and titanium-palladium master alloy fragments according to a mass ratio of 8-9:2-1, and mix them evenly.

[0012] Step 5, cold pressing of titanium-palladium electrode blocks: The mixture from step 4 is loaded into a steel cold pressing mold of fixed size and pressed into a blank, i.e., titanium-palladium electrode, under a pressing pressure of 600-800MPa; no pressure is held or pressure is held for 3-10 seconds;

[0013] Step Six, Preparation of Titanium-Palladium Alloy Ingot: The titanium-palladium electrode is repeatedly melted in the vacuum consumable electrode region to obtain the titanium-palladium alloy ingot; that is, it is melted little by little while solidifying little by little, in order to ensure that the material composition distributed relatively evenly in the previously formed electrode does not segregate; titanium and palladium have a large difference in density. If they are simply mixed, pressed into shape, and then the electrode is remelted, the unmelted part will expand under the action of the surrounding high temperature, causing the palladium mixed in the titanium to flow (palladium will drift in the liquid phase), thus affecting the uniformity.

[0014] Step 7, Homogenization Annealing: The titanium-palladium alloy ingot is homogenized and annealed in a vacuum annealing furnace to obtain the final product. This homogenization annealing process utilizes interatomic diffusion to further homogenize the two components and also helps to eliminate dendrites or minor segregation formed during remelting, as well as some lattice distortions.

[0015] Furthermore, in step one, the sponge titanium is commercially available grade 0 sponge titanium, and the purity of the palladium fragments is ≥99%.

[0016] Furthermore, in step two, the vacuum degree of the vacuum induction melting furnace is 9×10⁻⁶. -3 Pa~6×10 -4 Pa, the current of the vacuum induction melting furnace is 20-40A.

[0017] Furthermore, in step two, the rapid cooling is achieved by a water-cooled copper roller at 2000-5000 rpm.

[0018] Furthermore, in step four, physical mixing is carried out in a blade-type mixer for surface sputtering of titanium, with a blade rotation speed of 200-500 rpm and a mixing time of 30-60 minutes.

[0019] Furthermore, in step four, after physical mixing, a random sample of the mixture is taken and its uniformity is observed under a microscope. Alternatively, for the mixture, a sampling circle is randomly determined, the mass of the particles in this sampling circle is weighed, and the number of particles in this circle is counted. The deviation is then calculated using the following formula:

[0020]

[0021] Where: M x With m xThese represent the total number of particles and the total mass of the corresponding particles contained within a sampling circle of radius R, where r is the radius of the mixed particles, i.e., the particle radius of the sponge titanium; C′0 is a constant, ranging from 1 to 3; δ represents the deviation number. When the calculated deviation number δ is not greater than 5%, the mixing has reached the required uniformity. This step performs a uniformity check in the intermediate process to ensure the uniformity of the mixture between the intermediate alloy and the sponge titanium, further improving the uniformity of the distribution of the titanium-palladium alloy obtained from subsequent electrode remelting. If the calculated deviation number δ is greater than 5%, continue mixing in a blade mixer at a speed of 100-300 rpm for 60-120 minutes, but generally not exceeding 3 hours.

[0022] Furthermore, in step five, the density of the titanium-palladium electrode is 4.0–4.3 g / cm³. 3 .

[0023] Furthermore, in step six, the arc melting is carried out in a vacuum consumable electrode furnace with a vacuum degree of 1 Pa to 0.01 Pa, an arc ignition current of 1 to 2 kA, a melting current of 2 to 3 kA, and a voltage of 20 to 25 V; the axial movement speed of the consumable electrode is controlled at 10 to 20 mm / min to achieve gradient zone melting.

[0024] Furthermore, in step seven, the titanium-palladium alloy ingot is held at 550–600°C for 6–10 hours in a vacuum annealing furnace with a vacuum degree of 10. -1 ~10 -3 Pa, followed by furnace cooling, yields the product. The homogenization annealing temperature of 550–600℃ is chosen based on the Ti-Pd phase diagram to ensure that the final product is equiaxed α-titanium. If the temperature exceeds 600℃, β-titanium will form. If the temperature is below 550℃, the homogenization annealing will not be effective, as atomic diffusion will be too slow to eliminate dendrites formed during casting.

[0025] The homogeneous titanium-palladium alloy prepared by the above-mentioned method is used in the fields of medical and health care and petrochemical industry.

[0026] The beneficial effects of this invention are:

[0027] This invention achieves high compositional homogeneity by synergistically blending pre-fabricated titanium-palladium master alloy fragments with sponge titanium. The titanium-palladium master alloy is prepared by rapidly cooling (spinning) the melt after uniformly mixing sponge titanium and palladium fragments. The vigorous stirring in the liquid state promotes the mutual dissolution or reaction of Ti and Pd, resulting in a titanium-palladium master alloy strip with uniform composition, easily controllable thickness and width, and easy breakage into fragments with shapes and sizes similar to sponge titanium. This facilitates uniform mixing during the subsequent pressing and blending of sponge titanium and the master alloy, eliminating the need for special treatment of the master alloy strips. Elemental segregation can be suppressed, resulting in a homogeneous master alloy, which can then be mechanically crushed into fragments with particle sizes matching those of sponge titanium.

[0028] This invention involves high-speed mixing of intermediate alloy fragments and sponge titanium at a specific mass ratio. The similar morphological characteristics of the two materials achieve three-dimensional uniform dispersion. Because the amount of titanium-palladium intermediate alloy added is relatively greater than the amount of palladium powder added, and the shape and size of the intermediate alloy are comparable to those of sponge titanium, the pressed electrode exhibits better compositional uniformity. After high-pressure cold pressing, a density of 4.0–4.3 g / cm³ is obtained. 3 The composite electrode block exhibits significantly better compositional uniformity than the traditional direct mixing process of palladium powder. Multiple gradient meltings are performed using a vacuum consumable electrode furnace. This successive remelting not only eliminates metallurgical defects but also helps purify the alloy. Finally, vacuum annealing achieves atomic-scale diffusion homogenization, resulting in a high-quality titanium-palladium alloy ingot with no segregation and low impurities. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the preparation of titanium-palladium intermediate alloy thin strips by rapid quenching of melt according to an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of a physical mixing device for sponge titanium and intermediate alloy fragments according to an embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of sampling the mixture according to an embodiment of the present invention.

[0033] Figure 4a This is a scanning electron microscope image of the titanium-palladium alloy prepared in Example 1 of the present invention.

[0034] Figure 4b yes Figure 4a Distribution of the alloying element Ti.

[0035] Figure 4c yes Figure 4a Distribution of Pd, an alloying element.

[0036] Figure 5 This is the metallographic structure of the equiaxed grain TiPd alloy obtained in Example 1 of the present invention.

[0037] Figure 6 This is the macroscopic morphology of the titanium-palladium master alloy prepared by melt rapid quenching in Example 1 of the present invention.

[0038] Figure 7The morphology of TiPd alloy powder, which is similar to that of sponge titanium, is formed by melt rapid quenching in Embodiment 1 of the present invention.

[0039] Figure 8 This is the metallographic structure of the titanium-palladium alloy prepared in Example 2 of the present invention.

[0040] Figure 9 This is the microstructure of the titanium-palladium alloy prepared in Example 3 of the present invention.

[0041] Figure 10a This is the microstructure of the titanium-palladium alloy prepared in Comparative Example 1.

[0042] Figure 10b This is the microstructure of the titanium-palladium alloy prepared in Comparative Example 2.

[0043] Figure 10c This is the microstructure of the titanium-palladium alloy prepared in Comparative Example 3.

[0044] In the diagram, 1. base, 2. support leg, 3. mixing box, 4. hopper, 5. side plate, 6. discharge port, 7. sleeve box, 8. tie rod, 9. blade, 10. rubber plate, 11. spring, 12. reinforcing rod; 13. quartz tube, 14. molten metal, 15. heater coil, 16. molten metal jet, 17. thin strip, 18. water-cooled copper roller. Detailed Implementation

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1,

[0047] A method for preparing a homogeneous titanium-palladium alloy includes the following steps:

[0048] Step 1, Raw Material Preparation: Commercially available titanium sponge (Grade 0) and palladium fragments (particle size 150 mesh, purity ≥99%) are used. Grade 0 commercially available titanium sponge is characterized by high purity (99.7%–99.8%) and low impurity content, avoiding the impact of these impurities on the subsequent addition of a small amount of Pd (which may form compounds or dissolve with Pd); the particle size of the titanium sponge is 150 mesh.

[0049] Step 2, Preparation of the titanium-palladium intermediate alloy strip: Sponge titanium and palladium are weighed at a mass ratio of 98:2 and placed in a vacuum of 1×10⁻⁶. -3The material is rapidly melted in a vacuum induction furnace of the Pa melt quenching equipment with a current of 30A and accompanied by magnetic stirring for 5 minutes. After melting, it is left to stand for 5 minutes, and then argon gas is introduced. Under argon protection (argon gas pressure 0.1MPa), it is rapidly cooled with a water-cooled copper roller 18 at 3000 rpm to form a titanium-palladium master alloy strip with a thickness of 50 micrometers and a width of 8mm. The titanium-palladium master alloy strip solidifies rapidly under strong stirring, without time for precipitation and segregation. On the other hand, it is easy to break, and will not introduce other impurities in the subsequent crushing or pressing process, thus ensuring the purity of the overall alloy.

[0050] Step 3: Fragmentation of the titanium-palladium master alloy: The titanium-palladium master alloy prepared in Step 2 is crushed into titanium-palladium master alloy fragments (chips) using a crusher. The crusher shell is made of titanium alloy, and the blades are made of quenched wear-resistant steel 9SiCr with TiN sputtered surface. This not only achieves high strength and wear resistance but also prevents other impurity elements from mixing into the titanium-palladium. The size of the titanium-palladium master alloy fragments is the same as the particle size of sponge titanium.

[0051] Step four, mixing of sponge titanium and titanium-palladium master alloy: Weigh sponge titanium and titanium-palladium master alloy sheets at a mass ratio of 9:1, and mix them in a blade mixer at 300 rpm for 40 minutes. Utilize the mixture... Figure 3 The sampling method shown involves randomly selecting a sampling circle for the mixture, weighing the particles within this circle, counting the number of particles in the circle, and then calculating the deviation using the formula below:

[0052]

[0053] Where: M x With m x These are the total number of particles contained within a sampling circle of radius R and the total mass of the corresponding particles, respectively. r is the radius of the particles in the mixture (the particle radius of sponge titanium), C′0 is a constant, which is taken as 1 to 3 here; δ represents the deviation number. When the calculated deviation number δ is not greater than 5%, the mixing has reached the required uniformity.

[0054] Step 5, Cold pressing of the titanium-palladium electrode block: The mixture from Step 4 is loaded into a steel cold pressing mold of fixed size (the mold size can be adjusted arbitrarily according to production needs; the loading amount is the product of the mold cavity volume and the density of titanium). It is pressed under a pressure of 700 MPa for 3 seconds to form a blank with a certain strength (ensuring by density) and a certain shape (ensuring by the mold), i.e., the titanium-palladium electrode, with a density of 4.2 g / cm³. 3 .

[0055] Step 6, Preparation of titanium-palladium alloy ingot: The titanium-palladium electrode obtained in Step 5 is placed into a vacuum consumable electrode furnace (vacuum degree is 1Pa) and melted twice with a process gradient of arc ignition current of 1.5kA, melting current of 2.5kA and voltage of 22V (the ingot size obtained in the first melting is the same as the electrode size in Step 5, and the ingot size obtained in the second melting can be set by the user according to their needs) to obtain a titanium-palladium alloy ingot; the axial movement speed of the consumable electrode is 10mm / min.

[0056] Step 7, Homogenization Annealing: The titanium-palladium alloy ingot obtained in Step 6 is held at 580℃ for 8 hours in a vacuum annealing furnace with a vacuum degree of 10. -2 Pa, followed by furnace cooling (placed in a furnace with the power off and allowed to cool naturally under the same vacuum) to obtain a titanium-palladium alloy ingot (equiaxed grain TiPd alloy) with both uniform microstructure and composition.

[0057] The microstructure and elemental distribution of the titanium-palladium alloy prepared in Example 1 are as follows: Figures 4a-4c As shown, the distribution is very uniform. Figure 5 The microstructure of the TiPd alloy with equiaxed grains obtained after complete homogenization annealing in Example 1 is shown. The distribution of titanium and palladium is very uniform, and other impurities and phases are almost not visible around the α-titanium grains.

[0058] In Example 1, a portion of sponge titanium was mixed with palladium at a mass ratio of 98:2 to prepare a titanium-palladium master alloy ribbon according to the required titanium target alloy mass ratio. Compared with directly mixing all sponge titanium and palladium to prepare the titanium target alloy, the palladium content is higher, which is beneficial to improving the uniformity of titanium and palladium distribution. The ribbon was prepared by melt quenching. According to the Ti-Pd alloy phase diagram, the two are completely miscible at high temperatures. Melting allows Pd to completely dissolve in titanium, while rapid quenching prevents Pd precipitation, forming TiPd instead of Ti2Pd or TiPd3. This avoids compositional segregation during solidification, ensuring uniform distribution and laying a solid foundation for subsequent electrode remelting. The ribbon thickness is 40-60 micrometers and the width is 5-10 mm, which facilitates rapid quenching and subsequent crushing or pulverization. The morphology of the titanium-palladium master alloy ribbon obtained in step two of Example 1 after preliminary fragmentation is shown below. Figure 6 As shown, the morphology of the sponge titanium and titanium-palladium alloy mixture after step four of Example 1 is as follows. Figure 7 As shown.

[0059] Example 2,

[0060] A method for preparing a homogeneous titanium-palladium alloy includes the following steps:

[0061] Step 1, Raw material preparation: Commercially available sponge titanium (grade 0) and palladium fragments (particle size 100 mesh, purity ≥99%) are used; the particle size of the sponge titanium is 100 mesh.

[0062] Step 2, Preparation of the titanium-palladium intermediate alloy strip: Sponge titanium and palladium are weighed at a mass ratio of 96:4 and placed in a vacuum of 9×10⁻⁶. -3 The material is rapidly melted in a vacuum induction melting furnace in the Pa melt quenching equipment with a current of 40A and accompanied by magnetic stirring for 3 minutes. After melting, it is left to stand for 3 minutes, and then argon gas is introduced. Under argon protection (argon gas pressure 0.3MPa), it is then rapidly cooled with a water-cooled copper roller 18 at 2000 rpm to form a titanium-palladium intermediate alloy strip with a thickness of 40 micrometers and a width of 5mm.

[0063] Step 3, Titanium-Palladium Master Alloy Fragmentation Process: The titanium-palladium master alloy prepared in Step 2 is crushed into titanium-palladium master alloy fragments (shavings) using a crusher. The size of the titanium-palladium master alloy fragments is the same as the particle size of sponge titanium.

[0064] Step four, mixing of sponge titanium and titanium-palladium master alloy: Weigh sponge titanium and titanium-palladium master alloy sheets at a mass ratio of 8:2, and mix them in a blade mixer at a speed of 200 rpm for 60 minutes. Use the mixture... Figure 3 Sampling is performed as shown, and the calculated deviation δ is no greater than 5%.

[0065] Step 5, Cold pressing of the titanium-palladium electrode block: The mixture from Step 4 is loaded into a steel cold pressing mold of fixed size (the mold size can be adjusted arbitrarily according to production needs; the loading amount is the product of the mold cavity volume and the density of titanium). Under a pressing pressure of 800 MPa, it is pressed into a blank with a certain strength (ensuring by density) and a certain shape (ensuring by the mold), i.e., the titanium-palladium electrode, with a density of 4.3 g / cm³. 3 .

[0066] Step 6, Preparation of titanium-palladium alloy ingot: The titanium-palladium electrode obtained in step 5 is placed into a vacuum consumable electrode furnace (vacuum degree is 0.05Pa) and melted three times with an arc starting current of 1kA, a melting current of 3kA, and a voltage of 20V to obtain a titanium-palladium alloy ingot; the axial movement speed of the consumable electrode is 15mm / min; the process parameters for the three meltings are the same. This step is vacuum consumable electrode zone melting, and the cooling solidification and heating melting rates are consistent, melting and cooling occur simultaneously.

[0067] Step 7, Homogenization Annealing: The titanium-palladium alloy ingot obtained in Step 6 is held at 550℃ for 10 hours in a vacuum annealing furnace with a vacuum degree of 10. -1 Pa, followed by furnace cooling, yields a titanium-palladium alloy ingot with uniform microstructure and composition.

[0068] Figure 8 The microstructure of the titanium-palladium alloy prepared in Example 2 is shown. The titanium and palladium are evenly distributed, and no obvious component segregation or impurities are visible.

[0069] Example 3,

[0070] A method for preparing a homogeneous titanium-palladium alloy includes the following steps:

[0071] Step 1, Raw material preparation: Commercially available sponge titanium (grade 0) and palladium fragments (particle size 200 mesh, purity ≥99%) are used; the particle size of the sponge titanium is 200 mesh.

[0072] Step 2, Preparation of the titanium-palladium intermediate alloy strip: Titanium sponge and palladium are weighed at a mass ratio of 97:3 and placed in a vacuum of 0.6 × 10⁻⁶. -3 The material is rapidly melted in a vacuum induction melting furnace in the Pa melt quenching equipment with a current of 20A and accompanied by magnetic stirring for 10 minutes. After melting, it is left to stand for 10 minutes, and then argon gas is introduced. Under argon protection (argon gas pressure 0.5MPa), it is rapidly cooled with a water-cooled copper roller 18 at 5000 rpm to form a titanium-palladium intermediate alloy strip with a thickness of 60 micrometers and a width of 10 mm.

[0073] Step 3, Titanium-Palladium Master Alloy Fragmentation Process: The titanium-palladium master alloy prepared in Step 2 is crushed into titanium-palladium master alloy fragments (shavings) using a crusher. The size of the titanium-palladium master alloy fragments is the same as the particle size of sponge titanium.

[0074] Step four, mixing of sponge titanium and titanium-palladium master alloy: Weigh sponge titanium and titanium-palladium master alloy sheets at a mass ratio of 7:3, and mix them in a blade mixer at 500 rpm for 30 minutes. Utilize the mixture... Figure 3 Sampling is performed as shown, and the calculated deviation δ is no greater than 5%.

[0075] Step 5, Cold pressing of the titanium-palladium electrode block: The mixture from Step 4 is loaded into a steel cold pressing mold of fixed size (the mold size can be adjusted arbitrarily according to production needs; the loading amount is the product of the mold cavity volume and the density of titanium). It is pressed under a pressure of 600 MPa for 10 seconds to form a blank with a certain strength (ensuring by density) and a certain shape (ensuring by the mold), i.e., the titanium-palladium electrode, with a density of 4.0 g / cm³. 3 .

[0076] Step 6, Preparation of titanium-palladium alloy ingot: The titanium-palladium electrode obtained in step 5 is placed into a vacuum consumable electrode furnace (vacuum degree is 0.01Pa) and melted four times with an arc starting current of 2kA, a melting current of 2kA, and a voltage of 25V to obtain a titanium-palladium alloy ingot. The axial movement speed of the consumable electrode is 20mm / min. The process parameters for the four meltings are the same.

[0077] Step 7, Homogenization Annealing: The titanium-palladium alloy ingot obtained in Step 6 is held at 600℃ for 6 hours in a vacuum annealing furnace with a vacuum degree of 10. -3 Pa, followed by furnace cooling, yields a titanium-palladium alloy ingot with uniform microstructure and composition.

[0078] Figure 9 The microstructure of the titanium-palladium alloy prepared in Example 3 shows that the titanium and palladium are evenly distributed, and no obvious component segregation or impurities are visible.

[0079] In step two of Examples 1-3, vacuum induction melting melts the metal based on the principle of electromagnetic induction. The temperature is controlled by the applied frequency and current (determined through multiple experiments; an auxiliary infrared thermometer shows a temperature of 1800–1900°C). The melting time also depends on the amount of raw material added, determined through multiple experiments, or by observing the alloy melting through an observation port (melting time is generally about 15–25 minutes). After melting, the metal is left to stand for about 3–10 minutes before being poured through a casting riser onto a high-speed rotating water-cooled copper roller. Vacuum induction melting is integrated with the subsequent rapid cooling process and is not independent; therefore, it does not have a cooling rate on its own. The cooling end of the rapid cooling equipment has a dedicated casting riser, the size of which (10–15 mm wide, 3–7 mm high) matches the size of the water-cooled copper roller (a U-shaped groove 5–10 mm wide) to obtain the required thickness and width of the titanium-palladium intermediate alloy strip.

[0080] Schematic structures of titanium-palladium master alloy thin strips prepared by rapid quenching of melt in step two of Examples 1-3, as shown below. Figure 1 As shown, a high-pressure inert gas is introduced into the vacuum induction melting furnace. A heater coil 15 is provided on the outer wall of the quartz tube 13. Molten metal 14 is sprayed from the bottom of the quartz tube 13 onto the surface of the high-speed rotating water-cooled copper roller 18 in the form of a molten metal jet 16, forming a thin strip 17 of titanium-palladium intermediate alloy.

[0081] In step four of Examples 1-3, the mixing equipment used is a blade-type mixer, which is a high-efficiency mixing device with high mixing efficiency and low mixing intensity, ensuring that the materials reach the required particle size without being further crushed; the structure is as follows. Figure 2As shown, the equipment includes a mixing tank 3, with support legs 2 at the bottom and a base 1 at the lower end of the support legs 2. An inclined reinforcing rod 12 is provided between the support legs 2 and the base 1. A hopper 4 is provided at the top of the mixing tank 3, and an inverted V-shaped side plate 5 is provided directly below the hopper 4. A rubber plate 10 is provided on the inner wall of the mixing tank 3 below the side plate 5, and a spring 11 is provided at the bottom of the rubber plate 10. This spring 11 can provide a certain buffering effect when the material is poured, preventing the mixture from undergoing work hardening or phase change due to impact, or causing abrasion of the mixing tank (introducing other impurities). This allows the material to be mixed to flow slowly into the mixing tank, reducing the mixing intensity. A discharge port 6 is provided on the side wall of the mixing tank 3. An agitator with blades 9 is provided inside the mixing tank 3, and a drive device is provided on the outer bottom of the mixing tank 3. When the equipment is running, the drive device drives the agitator to rotate. The blades on the agitator apply shearing force, friction force, and tumbling force to the material, so that the materials of different components are fully contacted and evenly distributed in the container. One side wall of the mixing box 3 is equipped with a sleeve box 7 and a pull rod 8, which are used to collect finer mixed materials. If the material is too fine, it is not suitable for subsequent mixing and molding because these fine powders will fill the gaps in the coarse powder, affecting the proportion and uniformity.

[0082] Figure 3 In this process, the radius R of the sampling circle is much larger than the particle radius r, where R = 100r ~ 1000r. If the sampling circle is too small, the calculation cannot be completed or the accuracy of the calculation is poor. If the sampling circle is too large, it is difficult to count the number of particles in the circle, or it can be counted, but it takes too long.

[0083] Comparative Example 1,

[0084] A method for preparing a titanium-palladium alloy: steps 2 and 3 are omitted, and the rest is the same as in Example 1; that is, titanium powder and palladium powder are directly mechanically mixed (without using an intermediate alloy), cold-pressed, and then melted twice in the vacuum consumable electrode region to obtain the alloy.

[0085] The microstructure of the titanium-palladium alloy prepared in Comparative Example 1 is as follows: Figure 10a As shown, some dark gray, uneven titanium-palladium or palladium exists on the titanium matrix.

[0086] Comparative Example 2,

[0087] A method for preparing a titanium-palladium alloy: step seven is omitted; the remaining steps are the same as in Example 1. The metallographic structure of the obtained titanium-palladium alloy ingot is as follows. Figure 10b As shown, the composition is relatively uniform, but the tissue uniformity is not good.

[0088] Comparative Example 3,

[0089] A method for preparing a titanium-palladium alloy: steps 2, 3, and 6 are omitted, and the rest is the same as in Example 2; that is, titanium powder and palladium powder are mixed and melted three times in a vacuum arc furnace (which needs to be cold-pressed into blocks first).

[0090] The microstructure of the titanium-palladium alloy prepared in Comparative Example 3 is as follows: Figure 10c As shown, significant component segregation can be observed even at lower magnifications.

[0091] The homogeneous titanium-palladium alloy prepared by this invention is mainly used in the medical and health field (many medical products are made of titanium, and this material is usually used as the base material or raw material for these products), and also has some applications in the petroleum and chemical fields with special requirements. On the one hand, it requires high corrosion resistance, and on the other hand, it must have a certain mechanical strength. Therefore, the content of alloying elements cannot be high, and it must be a single-phase structure to avoid galvanic corrosion caused by multiphase structures, or abnormal grain growth or structural stress caused by the difference in potential energy on both sides of the grain boundaries due to grain inhomogeneity, thus leading to premature failure.

[0092] The prepared titanium-palladium alloy requires a palladium content not exceeding 0.2%, a very small amount requiring uniform distribution, which presents a significant challenge. This invention addresses this issue by first preparing a high-Pd-content intermediate alloy using sponge titanium and palladium fragments at a mass ratio of 96-98:4-2, employing multiple arc melting processes (vacuum induction melting in step two) to achieve optimal compositional homogeneity. Second, rapid melt quenching further enhances the uniformity of the intermediate alloy. Third, sponge titanium and titanium-palladium intermediate alloy fragments (with particle sizes comparable to sponge titanium) weighed at a mass ratio of 8-9:2-1 are mechanically mixed, and the mixing uniformity is verified. If the mass ratio of sponge titanium to palladium exceeds the specified range, it not only fails to meet the user's palladium content requirements but also increases costs, as palladium is very expensive; each additional 0.1% increases the price of the titanium-palladium alloy by approximately 5%. Fourth, remelting in the electrode region ensures that the mixing uniformity is not altered during the melting process. Fifth, homogenization annealing further improves any remaining uniformity, resulting in a highly uniform titanium-palladium alloy billet.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method of producing a homogenized titanium-palladium alloy, characterized by, It comprises the following steps: Step one, raw material preparation: titanium sponge with particle size of 100-200 mesh and palladium gold fragments with particle size of 100-200 mesh; Step two, put the titanium sponge and palladium gold fragments into the vacuum induction melting furnace in the melt quenching equipment according to the mass ratio of 96-98:4-2, quickly melt with magnetic stirring for 3-10 minutes, wait for 3-10 minutes after melting, and then quench into titanium-palladium intermediate alloy with thickness of 40-60 microns and width of 5-10 mm under argon protection; Step three, crush the titanium-palladium intermediate alloy into titanium-palladium intermediate alloy fragments with the same particle size as the titanium sponge; Step four, weigh the titanium sponge and titanium-palladium intermediate alloy fragments according to the mass ratio of 8-9:2-1, and physically mix them uniformly; Step five, put the mixture of step four into a steel cold pressing mold with fixed size, and press into a billet under a pressing pressure of 600-800 MPa, i.e. a titanium-palladium electrode; Step six, melt the titanium-palladium electrode in a vacuum consumable electrode furnace to obtain a titanium-palladium alloy ingot; Step seven, homogenize and anneal the titanium-palladium alloy ingot in a vacuum annealing furnace, and obtain the titanium-palladium alloy.

2. The method for preparing a homogeneous titanium-palladium alloy according to claim 1, characterized in that, In step one, the titanium sponge is commercially available grade 0 titanium sponge, and the purity of the palladium gold fragments is ≥99%.

3. The method for preparing a homogeneous titanium-palladium alloy according to claim 1, characterized in that, The vacuum degree of the vacuum induction melting furnace in the second step is 9x10 -3 Pa~6x10 -4 Pa, and the current of the vacuum induction melting furnace is 20~40A.

4. The method for preparing a homogeneous titanium-palladium alloy according to claim 1, characterized in that, In step two, the quenching is realized by a water-cooled copper roller at 2000-5000 rpm.

5. The method for preparing a homogeneous titanium-palladium alloy according to claim 1, characterized in that, In step four, the physical mixing is carried out in a blade mixer with titanium sputtering on the surface, the blade speed is 200-500 rpm, and the mixing time is 30-60 minutes.

6. The method for preparing a homogeneous titanium-palladium alloy according to claim 1, characterized in that, In step four, after physical mixing, randomly sample the mixture and observe its uniformity under a microscope, or randomly determine a sampling circle for the mixture, then weigh the mass of the particles in the sampling circle and count the number of particles in the circle, and calculate the deviation number by the following formula: wherein: M x and m x respectively are the total number of particles and the total mass of the corresponding particles contained in a sampling circle with radius R, r is the radius of the particles of the mixture, i.e. the radius of the particles of the titanium sponge; C'0 is a constant, taken to be 1-3; and δ represents the deviation number, the mixture being considered to be homogeneous when the calculated deviation number δ is not greater than 5%.

7. The method for preparing a homogeneous titanium-palladium alloy according to claim 1, characterized in that, In the step five, the density of the titanium-palladium electrode is 4.0-4.3 g / cm 3 .

8. The method for preparing a homogeneous titanium-palladium alloy according to claim 1, characterized in that, In step six, the arc melting is carried out in a vacuum consumable electrode furnace, the vacuum degree is 1 Pa-0.01 Pa, the starting arc current is 1-2 kA, the melting current is 2-3 kA, the voltage is 20-25 V, and the movement speed of the consumable electrode along the axial direction is 10-20 mm / min.

9. The method for preparing a homogeneous titanium-palladium alloy according to claim 1, characterized in that, In the seventh step, the titanium-palladium alloy ingot is kept in a vacuum annealing furnace at a temperature of 550-600 °C for 6-10 h, and the vacuum degree is 10 -1 -10 -3 Pa, and then the furnace is cooled, and the titanium-palladium alloy ingot is obtained.

10. The application of the homogeneous titanium-palladium alloy prepared by the preparation method of the homogeneous titanium-palladium alloy according to claim 1 in the fields of medical health and petroleum chemical industry.

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