CN111822711A - High-density titanium or titanium alloy parts and powder metallurgy filling method - Google Patents

Abstract

A high-density titanium or titanium alloy component and a powder metallurgy filling manufacturing method thereof belong to the field of powder metallurgy manufacturing of metal components. According to the method, metal powder is weighed according to the composition ratio of high-density titanium or titanium alloy parts; compacted after mixing to obtain a regular-shaped powder compact with a relative density of more than 80%; heated to 1000-1400° C. 2-30min to obtain a powder compact with a sintering degree of 20-90%; under the protection of vacuum or inert gas, perform rapid filling to obtain titanium or titanium alloy parts blanks; cool the titanium or titanium alloy parts blanks with the mold To below 900 ℃, take it out and perform finishing to obtain titanium or titanium alloy parts with high density and high metallurgical bonding degree. The method can realize the preparation of near-net-shaped dense titanium or titanium alloy parts, and has the advantages of low energy consumption and short process flow.

Description

High-density titanium or titanium alloy parts and powder metallurgy filling method

technical field

The invention belongs to the field of powder metallurgy manufacturing of metal parts, and provides a high-density titanium or titanium alloy part and a powder metallurgy filling manufacturing method thereof. A powder metallurgy manufacturing method for powder blanks of different sizes and sizes, and then sintering the powder blanks, which is a powder blank with a regular shape that is filled under high temperature and vacuum or protective atmosphere, and densified and further formed during the filling process. Method of manufacture of consolidated titanium alloy parts.

Background technique

Titanium and titanium alloys have the characteristics of low density, high specific strength and corrosion resistance, and are widely used in aerospace, machinery manufacturing, national defense, military and biomedical fields. In traditional metal parts manufacturing, titanium alloy parts are mainly manufactured by casting, forging or powder metallurgy processes. For the casting process, because the titanium alloy liquid is very active, the cost of the titanium alloy melting and the mold material for casting is very high, so the cost of the titanium alloy casting is very high. At the same time, due to casting defects and coarse solidification structure of casting, the mechanical properties of cast titanium alloy parts cannot reach the level of mechanical properties of ingot metallurgical titanium alloy materials. As for the forging process, under the premise of suitable forging process conditions, the comprehensive mechanical properties of the titanium alloy parts manufactured by the forging process are very good, and can reach the mechanical properties level of ingot metallurgical titanium alloys. Due to the limitation and the need to remove the brittle α layer with excessive surface oxygen content, the size and shape of the part blank produced by the titanium alloy forging process is very different from the final part, resulting in usually more than 50% of the material to be removed by machining. rate is very low. Titanium alloys are not easily machineable metals and are expensive to machine, which results in high costs for components made through the forging-machining process.

The powder metallurgy process has the advantages of near-net shaping. The shape and size of the parts (such as gears) are produced by molding the titanium alloy pre-alloyed powder, or the mixed powder obtained by mixing the titanium powder and other metal powders according to the requirements of the alloy composition. The relative density of the powder blank generally reaches more than 90%, and then the powder blank is placed in a vacuum furnace for sintering and densification to obtain titanium alloy sintered parts with a relative density of more than 95%. Because it is difficult to completely eliminate the residual pores in the parts, and at the same time, the microstructure of the titanium alloy is coarse due to high temperature sintering, the mechanical properties of the parts made by the traditional powder metallurgy process cannot reach the mechanical properties of the ingot metallurgical titanium alloy. The material and mechanical properties of titanium alloy powder sintered parts can be improved by forging or hot isostatic pressing, but at an additional cost. Due to the limited fluidity of the powder, the shape of the parts produced by the traditional powder molding and sintering process is relatively simple or relatively symmetrical. Through the metal powder injection molding (English: Metal Injection Molding (MIM)) process, complex-shaped titanium alloy pre-alloys or mixed powder powder blanks can be manufactured, and then sintered powder blanks can be used to manufacture complex-shaped parts, but this process is only suitable for Manufacture of parts with a single mass of less than 500 grams.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the present invention provides a high-density titanium or titanium alloy parts and a powder metallurgy filling manufacturing method thereof. The method is a novel short-flow, near-net-shape, low-cost, titanium Or powder metallurgy manufacturing method of titanium alloy parts. It is based on the fine-grained titanium or titanium alloy material obtained by powder consolidation and alloying at high temperature, which has good fluidity, and can fill the closed cavity under the drive of pressure, so as to obtain a close-fitting cavity defined by the mold cavity. Net shape titanium or titanium alloy component blanks. Through this method, the effect of thermoplastic injection molding technology can be achieved, and the heated powder blank can be quickly turned into a dense part blank with mechanical and other physical properties of titanium alloy. The method can realize the preparation of near-net-shaped dense titanium or titanium alloy parts, and has the advantages of low energy consumption and short process flow.

A powder metallurgy filling manufacturing method for high-density titanium or titanium alloy parts of the present invention comprises the following steps:

(1) Mixed

Weigh the metal powder according to the composition of high-density titanium or titanium alloy parts and the mass percentage of each component;

Mix the metal powder evenly to obtain a mixed powder;

(2) compaction

compacting the mixed powder to obtain a regular-shaped powder compact with a relative density of more than 80%;

(3) Heating and heat preservation

Under the protection of vacuum or inert gas, the regular shape powder compact is heated to 1000-1400 ℃, and the temperature is kept for 2-30 minutes to obtain a powder compact with a sintering degree of 20-90%;

(4) Filling

Under the protection of vacuum or inert gas, the heated powder compact whose temperature is controlled at 1000-1400 ℃ is placed in the filling mold of titanium or titanium alloy parts;

The heated powder compact is pressurized, and the heated powder compact material is driven to flow at a high temperature for rapid filling, until the heated powder compact is completely filled with titanium or titanium alloy parts and the filling mold cavity is obtained. Titanium or titanium alloy parts blanks;

Wherein, the heated powder compact is subjected to hot extrusion during the filling process, the extrusion ratio is 5:1-100:1, the pressing pressure is 10-1000MPa, more preferably 100-500MPa, and the pressing time is longer than or equal to the filling time, preferably 0.1-5min.

(5) Post-processing

The titanium or titanium alloy parts blanks are cooled to below 900 ℃ with the mold, taken out, and subjected to finishing to obtain high-density titanium or titanium alloy parts.

In the step (1), in the metal powder, the raw materials of the titanium powder are titanium metal and/or titanium hydride powder, and the raw materials of other metal powders in the titanium alloy are metal powder or metal alloy powder. The composition of the prepared high-density titanium alloy parts is determined.

In the step (1), the particle size of the metal powder is below 200 meshes.

In the step (1), the mixing is uniformly carried out by means of mechanical ball milling.

In the step (2), one of molding or cold isostatic pressing is used for the green compact.

In the step (2), the pressure of molding or cold isostatic pressing is 100-1000MPa, and the pressure holding time is 1-10min.

In the step (2), the green compact can be one of unidirectional compression molding or bidirectional compression molding; When the temperature is 100-500 °C, the compaction process needs to be carried out in an argon protected environment.

In the step (2), the regular shape can be one of cylindrical, rectangular and square.

In the step (3), the heating rate is 5-200°C/min, preferably 35-100°C/min.

In the step (3), the equipment used for heating is one of an induction furnace, a microwave oven, an electric furnace, and a plasma heat treatment furnace; the heating time is preferably 5-20 min, and this step realizes partial sintering of the powder compact, and partial sintering of the powder compact. The sintering rate of sintering is 20-90%.

In the step (3), the vacuum is a vacuum condition of absolute air pressure≤200Pa; the protection of inert gas is preferably argon gas protection with oxygen content≤200ppm.

In the step (3), when the raw material of the titanium powder contains titanium hydride, during the heating process, the titanium hydride powder particles are in-situ dehydrogenated into titanium powder particles.

In the step (4), the extrusion speed of the hot extrusion is 10-30 mm/s.

In the step (4), the titanium or titanium alloy parts filling mold can be preheated, and the preheating temperature is room temperature -550°C.

In the step (4), the pressing and filling of the heated powder compact are carried out under vacuum or under the protection of an inert gas selected for the compact.

In the step (4), the vacuum is a vacuum condition of absolute air pressure≤200Pa; the protection of inert gas is preferably argon gas protection with oxygen content≤200ppm.

In the step (4), the relative density of the titanium or titanium alloy parts blank is ≥98.5% and the degree of metallurgical bonding between the powder particles is ≥98%.

In the step (5), when titanium hydride is contained in the raw material of the titanium powder, a thorough dehydrogenation treatment is required before finishing. Incubate for 1-10h.

In the described step (5), the finishing is cutting, heat treatment and machining, wherein the heat treatment and machining are performed according to the heat treatment and machining methods commonly used in the titanium or titanium alloy product manufacturing industry;

In the powder metallurgy filling method for high-density titanium or titanium alloy parts, cutting and machining to remove materials account for ≤15% of the total weight of the entire titanium or titanium alloy parts.

In the step (5), the heat treatment and machining are performed according to the requirements of the microstructure, mechanical properties and shape and size of the titanium or titanium alloy parts.

In the powder metallurgy filling method for high-density titanium or titanium alloy parts, the time from step (2) compacting to step (4) forming is 30-40 minutes.

In the step (4), the titanium or titanium alloy parts filling mold is a mold frame and a mold cavity formed by the mold frame.

In the powder metallurgy filling method for high-density titanium or titanium alloy parts, the titanium parts are industrial pure titanium parts, and the titanium alloy parts can be Ti-6Al-4V titanium alloy parts (the numbers are alloys). Element mass percentage, domestic alloy grade is TC4 titanium alloy).

The industrial pure titanium parts of the present invention are prepared by the above method, the relative density is ≥98.5%, the tensile strength is 600-800MPa, and the elongation is 15-25%.

A Ti-6Al-4V titanium alloy part of the present invention is prepared by the above method, the relative density is ≥98.5%, the tensile strength is 900-1200MPa, and the elongation is 10-20%.

The invention relates to a high-density titanium or titanium alloy part and a powder metallurgy filling manufacturing method thereof. The main metal material processing principles are: (1) The rapid densification of the powder blank is realized by the high-temperature plastic deformation of the powder particles in the powder blank , instead of relying on a slower material migration mechanism to achieve the densification of the powder blank as in the traditional pressureless sintering process; (2) the powder particles undergo plastic deformation during the high-temperature filling process of the powder blank into a cross-sectional width of less than 20μm At the same time, during the filling process of the powder blank, the thin strips and flakes of different components are pressed together to make the atoms diffuse between the thin strips and flakes of different components rapidly to achieve alloying; (3) During the filling process The thin strips and sheets that are pressed together undergo rapid diffusion welding to achieve the consolidation of powder particles; (4) The metal material is below the melting point, but in the temperature range close to the melting point, the flow stress is very low, and it can be like a fluid under static pressure. (5) The metal material is rapidly plastically deformed during the filling process, causing dynamic recrystallization, resulting in the formation of fine grains. At the same time, due to the relatively short time of the material at high temperature, the crystal is limited. The grains grow up, so that the grains of the material are equiaxed and small, which is beneficial to obtain excellent mechanical properties.

A high-density titanium or titanium alloy part and its powder metallurgy filling manufacturing method of the present invention have the following advantages:

(1) Short process: The process includes powder mixing, compaction, heating and heat preservation, forming and post-processing. It can be completed within 40 minutes from pressing to forming, which is helpful for automation.

(2) Near-net shape: For parts with complex shapes, the shape and size of the part blank prepared by this method are very close to the final shape and size of the part. To obtain the final part, the material required to be removed by cutting and machining does not exceed 15% of the mass of the entire part blank, and the material utilization rate is much higher than that of conventional forgings.

(3) Low energy consumption and low environmental impact: This method does not require melting metal, and at the same time, the material utilization rate is high, so the energy consumption per kilogram of parts and components will be significantly lower than that of casting and forging processes. At the same time, the heating and forming of the powder blank are carried out under the protection of vacuum or inert gas, and there is no harmful gas emission and no impact on the environment.

(4) Good mechanical properties of the material: The titanium alloy parts manufactured by this process have high density (relative density exceeding 98.5%), small microstructure, high strength and good plasticity of the material, which are superior to cast titanium alloy parts and are comparable to forging. The mechanical properties of titanium alloy parts are comparable or better.

(5) The manufacturing method of the present invention is to heat the pure titanium powder compact or the titanium and other metal powder mixed compact to partially sinter and soften it to form a continuous high-temperature solid material blank containing voids, and then drive the material by driving the compact. Filling the mold cavity with the blank causes the plastic deformation of the powder particles, turning them into flakes or thin strips with a thickness or diameter of less than 20 μm, and pressing them together at the same time. Rapid densification and rapid diffusion of atoms in powder particles to achieve rapid welding and obtain titanium or titanium alloy solid materials. At the same time, if the powder compact contains powder particles of different components, the atoms of different elements diffuse into each other to achieve rapid alloying and generate titanium alloys. The desired part shape is also obtained by filling the mold cavity. Compared with the traditional powder metallurgy method, the densification process is realized by simply relying on the atomic migration of powder substances during the sintering process, and the speed is faster, and the parts produced are denser. In terms of molding, compared with the metal powder injection molding and sintering process, the quality of a single component that can be manufactured by the method of the present invention can be larger and is not limited.

Description of drawings

Figure 1: A schematic longitudinal cross-sectional view of the titanium or titanium alloy parts filling mold used in the embodiment of the present invention; wherein, 1 is the extrusion cylinder, 2 is the extrusion nozzle part, and 3 is the titanium or titanium alloy parts cavity part.

Fig. 2: The rough drawing of Ti-6Al-4V titanium alloy parts prepared in Example 1 of the present invention: (a) front side, (b) back side.

Figure 3: The cross section of the Ti-6Al-4V titanium alloy part prepared in Example 1 of the present invention.

Figure 4: The surface topography of the high-density Ti-6Al-4V titanium alloy parts prepared in Example 1 of the present invention.

Figure 5: In Example 1 of the present invention, the XRD patterns of the prepared high-density Ti-6Al-4V titanium alloy parts sampled at different positions; wherein, TC4-AF-1 is the top center of the TC4 unheated sample, TC4- AF-2 is the radial sampling of the radiation part, and TC4-AF-3 is the circumferential sampling of the edge part.

Figure 6: The metallographic photograph of the high-density Ti-6Al-4V titanium alloy parts prepared in Example 1 of the present invention.

Figure 7: Metallographic photograph (a) and XRD pattern (b) of the prepared high-density Ti-6Al-4V titanium alloy parts after vacuum annealing at 700°C for 6 hours in Example 1 of the present invention.

Figure 8: In Example 1 of the present invention, the tensile engineering stress-strain curve of the prepared high-density Ti-6Al-4V titanium alloy parts after vacuum annealing at 700°C for 6 hours.

Figure 9: In Example 2 of the present invention, the prepared high-density industrial pure titanium parts are sampled at different positions and XRD patterns before and after heat treatment; wherein, WHT-up is the upper part of the part before heat treatment, and WHT-down is before heat treatment The lower part of the part, HT-up is the upper part of the part after annealing, and HT-lower is the lower part of the part after annealing.

Figure 10: The metallographic photograph of the high-density industrial pure titanium parts prepared in Example 2 of the present invention before heat treatment.

Figure 11: The metallographic photograph of the prepared high-density industrial pure titanium parts after annealing at 700°C for 6 hours in Example 2 of the present invention.

Figure 12: In Example 2 of the present invention, the tensile engineering stress-engineering strain curve of the prepared high-density industrial pure titanium parts after annealing at 700°C for 6 hours; wherein, HT-under 1 is HT-under The center of the lower part of the annealed part, HT-lower 2 is the radial direction of the lower part of the annealed part, and HT-lower 3 is the circumferential direction of the lower part of the annealed part.

Detailed ways

The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to this example.

In the following embodiments, the argon gas protection is argon gas protection with an oxygen content of less than or equal to 200 ppm. The vacuum environment is an environment where the absolute pressure is lower than 200Pa.

Featured Example 1:

The present embodiment provides a powder metallurgy filling manufacturing method for high-density Ti-6Al-4V titanium alloy parts. The specific steps of the method are as follows:

Step 1: Mix

Weigh 4.5kg of hydrogenated titanium powder with a particle size of -200 mesh and a purity of 99.8%, and 0.5 kg of Al60V40 master alloy powder with a particle size of -200 mesh, placed in a mechanical ball mill and mixed at room temperature for 24 hours to obtain a The distribution ratio is Ti/Al60V40 mixed powder of Ti-6Al-4V (mass percentage).

Step 2: Place 4kg of mixed powder in a cylindrical mold with an inner cavity diameter of 115mm and a height of 450mm for molding to obtain a cylindrical Ti/Al60V40 mixed powder compact with a diameter of 115mm and a height of 100mm. Ti/Al60V40 is mixed Powder compact density: 3.85 g/cm ³ Relative density: 85.56%.

Step 3: Heat and keep warm

In a vacuum environment with an absolute pressure of 176Pa, the prepared Ti/Al60V40 mixed powder compact was subjected to induction heating, and the Ti/Al60V40 mixed powder compact was heated to 1250°C and kept for 5 minutes to obtain the heated Ti/Al60V40 mixed powder compact. Preform; the heated Ti/Al60V40 mixed powder compact is partially sintered, and the sintering degree is 80%.

Step 4: Filling

Then the heated Ti/Al60V40 mixed powder compact is moved by robot into the extrusion barrel in the preheated titanium or titanium alloy part filling die as shown in Figure 1. Pressurize the Ti/Al60V40 mixed powder compact with a hydraulic press through the upper indenter, the pressure is 200-800MPa, and the lowering speed is 15mm/s. Under the action of pressure, the Ti/Al60V40 mixed powder compact material flows, fills the cavity of titanium or titanium alloy parts, and obtains near-net-shaped Ti-6Al-4V titanium alloy parts blanks. The filling die for titanium or titanium alloy parts is shown in Figure 1, which mainly includes an extrusion nozzle part 2 and a titanium or titanium alloy part cavity part 3, and, in this embodiment, the titanium or titanium alloy parts cavity The part 3 includes an extrusion nozzle part 2, and an extrusion barrel 1 is arranged near the extrusion nozzle part 2; the extrusion barrel 1 is used to receive the powder compact; the extrusion nozzle part 2 is used to realize the extrusion and solidification of the powder compact. Knot; titanium or titanium alloy part cavity section 3, used to define the part blank shape. The preheating temperature of the filling mold for titanium or titanium alloy parts is 200-500 °C.

During the heating and heat preservation in step 3 and the powder compact filling in step 4, the Ti and Al60V40 powder particles undergo a diffusion reaction, and most of the Al60V40 powder particles are dissolved into the titanium matrix to achieve alloying and generate Ti-6Al-4V (mass percent) alloy (often called TC4 titanium alloy).

Step 5: Post-processing

Cool the prepared Ti-6Al-4V titanium alloy parts blank to 600°C and take it out in the air to obtain high-density Ti-6Al-4V titanium alloy parts;

Then, the high-density Ti-6Al-4V titanium alloy parts were annealed at 700 °C in a vacuum environment for 6 hours to obtain the annealed Ti-6Al-4V titanium alloy parts.

Observation of the prepared Ti-6Al-4V titanium alloy parts blank (see Figure 2) shows almost net shape. Observation of the material cross-section of the Ti-6Al-4V titanium alloy parts blank (see Figure 3) confirms that the Ti-6Al-4V titanium alloy parts have high density, with a relative density of 99% and powder particles. The degree of metallurgy in between is 98%.

The surface morphology of the prepared high-density Ti-6Al-4V titanium alloy parts is shown in Figure 4. It can be seen that after annealing, the prepared high-density Ti-6Al-4V titanium alloy parts have smooth surfaces and no defects. , and compared with Figure 2, only on the basis of the near-net-shaped Ti-6Al-4V titanium alloy parts blank in Figure 2, the material removed accounts for 5% of the total weight of the entire titanium or titanium alloy parts, indicating that the direct Fill the mold to obtain high-density Ti-6Al-4V titanium alloy parts.

The prepared high-density Ti-6Al-4V titanium alloy parts were subjected to X-ray analysis, metallographic scanning electron microscope observation, and tensile testing to obtain the microstructure and mechanics of the high-density Ti-6Al-4V titanium alloy parts and components. performance data.

Figure 5 shows the XRD patterns of the prepared high-density Ti-6Al-4V titanium alloy parts at different positions. It can be seen from Figure 5 that the XRD patterns of the samples at each position are basically the same, indicating that the high-density Ti-6Al-4V titanium The composition of the alloy parts is uniform. Figure 6 is the metallographic photo of the high-density Ti-6Al-4V titanium alloy parts. It can be seen from Figure 6 that the prepared titanium alloy parts have a typical fully dense lamellar structure. Figure 7 shows The metallographic photos and XRD patterns of the prepared Ti-6Al-4V titanium alloy parts after annealing; Figure 7 shows that the microstructure of the titanium alloy parts is basically unchanged after annealing; Figure 8 shows the prepared Ti-6Al The tensile engineering stress-strain curve of -4V titanium alloy parts material after annealing, it can be seen from this curve that the tensile strength of titanium alloy parts reaches 1080MPa, and the elongation at break reaches 10%.

Featured Example 2:

The present embodiment provides a powder metallurgy filling manufacturing method for high-density industrial pure titanium parts, and the specific steps of the method are as follows:

Step 1: Place 4.3 kg of hydrogenated titanium powder in a cylindrical mold with an inner cavity diameter of 115 mm and a height of 450 mm, and carry out molding to obtain a cylindrical industrial titanium powder compact with a diameter of 115 mm and a height of 112 mm, industrial The density of the titanium powder powder compact is: 3.70 g/cm ³ , and the relative density is: 82.2%.

Step 2: Inductively heat the prepared industrial titanium powder compacts in a vacuum environment with an absolute pressure lower than 175Pa. The average heating rate is: 50°C/min. The industrial titanium powder compacts are heated to 1250°C and kept for 5 minutes. , to obtain the heated industrial titanium powder compact; at this time, in the heated industrial titanium powder compact, part of the industrial titanium powder has been sintered, and the sintering degree is 60%;

Step 3: Then, the heated industrial titanium powder compact is moved by a robot into the extrusion barrel in the preheated titanium or titanium alloy parts filling mold shown in FIG. 1 . Use a hydraulic press to pressurize the industrial titanium powder compacts through the upper indenter, the pressure is 500MPa, and the lowering speed is 30mm/s. Under the action of pressure, the industrial titanium powder powder material flows, fills the cavity of titanium or titanium alloy parts, and obtains near-net-shaped industrial pure titanium parts blanks.

Cool the industrial pure titanium parts blank to 600 ℃ or below, and take it out from the mold in the air to obtain high-density industrial pure titanium parts.

High-density industrial pure titanium parts are annealed at 700°C in a vacuum environment for 6 hours to obtain annealed high-density industrial pure titanium parts.

X-ray analysis, metallographic and scanning electron microscope observations, and tensile tests are performed on the materials of the prepared parts blanks to obtain the microstructure and mechanical properties of the materials.

The prepared high-density industrial pure titanium parts were subjected to XRD analysis at different positions and before and after heat treatment. The XRD pattern is shown in Figure 9. It can be seen from Figure 9 that the industrial pure titanium parts are mainly α-Ti, and there is no obvious The impurity peaks, the XRD patterns of the samples at each position are basically the same, and the alloy composition uniformity is good.

The metallographic photo of the high-density industrial pure titanium parts before heat treatment is shown in Figure 10. It can be seen from the figure that the metallographic structure of the high-density industrial pure titanium parts before heat treatment is Widmanderstein, the structure is uniform, and there are some crystallites. group.

Figure 11 shows the metallographic photos of high-density industrial pure titanium parts after annealing at 700°C for 6 hours, indicating that the metallographic structure of pure titanium parts after annealing is equiaxed. The tensile engineering stress-engineering strain curve of high-density industrial pure titanium parts after annealing at 700°C for 6 hours is shown in Figure 12, indicating that the high-density industrial pure titanium parts are resistant to resistance after annealing at 700°C for 6 hours. The tensile strength can reach 600MPa, and the elongation is 16%-20%.

Featured Example 3:

A powder metallurgy filling manufacturing method for high-density titanium alloy parts, comprising the following steps:

(1) The titanium powder below 200 mesh and the Al60V40 intermediate alloy powder below 200 mesh required for the configuration of the alloy are uniformly mixed by mechanical ball milling to obtain a mixed powder with a ratio of Ti-3Al-2.5V (mass percentage);

(2) Under the argon protection environment, the mixed powder was placed in a compaction mold preheated to 200 °C, and cold isostatic pressing was used. Powder compact with a density of 83%;

(3) Under the protection of argon, the powder compact was heated to 1300°C at a heating rate of 50°C/min by microwave heating, and the temperature was maintained for 5 minutes to obtain the heated powder compact. The sintering degree of the heated powder compact is: 60%;

(4) Under the protection of argon gas, the heated powder compact is quickly transferred to the titanium or titanium alloy parts filling mold preheated to 400 °C;

(5) Under the protection of argon, pressurize the heated powder compact, first drive the heated powder compact to fill the cavity of the mold, and form a Ti-3Al-2.5V titanium alloy parts blank;

(6) Under the protection of argon gas, when the temperature of the Ti-3Al-2.5V titanium alloy parts blank drops to 900 ℃, open the mold and take out the Ti-3Al-2.5V titanium alloy parts blank.

(7) Remove the redundant part;

(8) Machining the titanium alloy parts blank to obtain Ti-3Al-2.5V titanium alloy parts.

Featured Example 4:

A powder metallurgy filling manufacturing method for high-density titanium alloy parts, comprising the following steps:

(1) The titanium hydride powder below 200 mesh and the Mo and Ni metal powder below 200 mesh required for the configuration of the alloy are uniformly mixed by mechanical ball milling to obtain a mixture of Ti-1.5Mo-2Ni (mass percentage) mixed powder;

(2) Under the argon protection environment, the mixed powder was placed in a compacting mold preheated to 500 ° C, and the molding method was adopted. powder compact;

(3) Under the protection of argon, the powder compact is heated to 1350°C at a heating rate of 100°C/min by plasma heating, and the temperature is maintained for 10 minutes to obtain the heated powder compact; at this time, the heated powder compact is obtained. The titanium hydride powder has been dehydrogenated to obtain titanium powder; the sintering degree of the heated powder compact is 50%;

(4) Under the protection of argon gas, the heated powder compact is quickly transferred to the titanium or titanium alloy parts filling mold preheated to 400 °C;

(5) Under the protection of argon gas, pressurize the heated powder compact, first drive the heated powder compact under the pressure of 500MPa, fill the cavity of the mold, and form a Ti-1.5Mo-2Ni titanium alloy parts blank;

(6) Under the protection of argon gas, when the temperature of the Ti-1.5Mo-2Ni titanium alloy parts blank drops to 900 ℃, open the mold and take out the Ti-1.5Mo-2Ni titanium alloy parts blank.

(7) Remove the redundant part;

(8) The titanium alloy parts blanks are kept at 750°C for 2 hours, thoroughly dehydrogenated, and then machined to obtain Ti-1.5Mo-2Ni titanium alloy parts.

Featured Example 5:

A powder metallurgy filling manufacturing method for high-density titanium alloy parts, the steps of which include:

(1) Mix titanium hydride and titanium powder with a particle size below 200 mesh in a mass ratio of 1:1 as the titanium source in the titanium alloy; measure the particle size with the Ti-0.2Pd (mass percent) titanium alloy ratio For the Pd metal below 200 mesh, the Pd metal and the titanium source raw material are mechanically ball milled and mixed to obtain a mixed powder;

(2) Bidirectional molding is performed by a room temperature compression mold, and the mixed powder is pressed into a cylindrical shape to obtain a powder compact; wherein, in the molding process, the pressure is 1000MPa, and the pressure holding time is 1min; the obtained powder compact has a relative density at 85%;

(3) heating with an electric furnace in a vacuum environment for 30 minutes, heating the powder compact to 1000°C, and keeping the temperature for 30 minutes; obtaining the heated powder compact with a sintering degree of 50%;

(4) In a vacuum environment, put the heated powder compact into a titanium or titanium alloy parts filling mold with a preheating temperature of 100°C;

In a vacuum environment, pressurize the heated powder compact, first drive the heated powder compact to extrude, the extrusion ratio is 5:1, the pressing pressure is 100MPa, the extrusion speed is 25mm/s, and then Refill into the cavity of the filling mold for titanium or titanium alloy parts to achieve forming;

(5) After the formed titanium alloy is cooled to 800 ℃ in the mold, the mold is opened, and the titanium alloy parts blank is taken out;

(6) Remove the excess part of the titanium alloy parts blank, heat treatment at 650 ° C for 10h, so as to completely dehydrogenate, heat treatment of the whole parts, and then partially machined to obtain Ti-0.2Pd titanium alloy parts .

Claims (10)

1. A powder metallurgy mold filling manufacturing method of a high-density titanium or titanium alloy part is characterized by comprising the following steps:

(1) mixing

Weighing metal powder according to the component composition of the high-density titanium or titanium alloy part and the mass percentage of each component;

uniformly mixing the metal powder to obtain mixed powder;

(2) green compact

Compacting the mixed powder to obtain a regular-shaped powder compact with the relative density of more than 80%;

(3) heating and heat preservation

Under the protection of vacuum or inert gas, heating the regular-shaped powder compact to 1000-1400 ℃, and preserving heat for 2-30min to obtain a powder compact with the sintering degree of 20-90%;

(4) filling type

Under the protection of vacuum or inert gas, placing the heated powder compact with the temperature controlled at 1000-1400 ℃ in a titanium or titanium alloy part mold filling mold;

pressurizing the heated powder pressed compact, driving the heated powder pressed compact material to flow at high temperature for rapid mold filling until the heated powder pressed compact completely fills the mold cavity of the mold for filling the titanium or titanium alloy part, and obtaining a blank of the titanium or titanium alloy part;

wherein the heated powder compact realizes hot extrusion in the mold filling process, the extrusion ratio is 5:1-100:1, the pressurization pressure is 10-1000MPa, and the pressurization time is more than or equal to the mold filling time;

(5) post-treatment

And cooling the titanium or titanium alloy part blank to below 900 ℃ along with the die, taking out, and performing finish machining to obtain the high-density titanium or titanium alloy part.

2. The powder metallurgy mold filling manufacturing method of the high-density titanium or titanium alloy part according to claim 1, wherein in the step (1), the raw material of the titanium powder in the metal powder is titanium metal and/or titanium hydride powder, the raw material of other metal powder in the titanium alloy is metal powder or metal alloy powder, and the proportion of each powder is determined according to the components of the manufactured high-density titanium alloy part; the particle size of the metal powder is 200 mesh or less.

3. The powder metallurgy mold filling manufacturing method for the high-density titanium or titanium alloy part according to the claim 1, wherein in the step (2), the compact is one of molded or cold isostatic pressed; the pressure of the mould pressing or cold isostatic pressing is 100-1000MPa, and the pressure maintaining time is 1-10 min.

4. The powder metallurgy mold filling manufacturing method for high-density titanium or titanium alloy parts according to claim 1, wherein in the step (3), the heating rate is 5-200 ℃/min; the heating equipment is one of an induction furnace, a microwave oven, an electric furnace and a plasma heat treatment furnace.

5. The powder metallurgy mold-filling manufacturing method for high-density titanium or titanium alloy parts according to claim 1, wherein in the step (4), the mold-filling mold for the titanium or titanium alloy parts is preheated, and the preheating temperature is room temperature to 550 ℃.

6. The powder metallurgy mold filling manufacturing method of the high-density titanium or titanium alloy part according to claim 1, wherein the vacuum is a vacuum condition with an absolute air pressure of 200Pa or less; the inert gas protection is argon gas protection with oxygen content less than or equal to 200 ppm.

7. The powder metallurgy mold filling manufacturing method for the high-density titanium or titanium alloy part according to the claim 1, wherein in the step (4), the relative density of the titanium or titanium alloy part blank is more than or equal to 98.5%, and the metallurgical bonding degree between the powder particles is more than or equal to 98%.

8. The powder metallurgy mold-filling manufacturing method of high-density titanium or titanium alloy parts according to claim 1, wherein in the step (5), when the raw material of the titanium powder contains titanium hydride, complete dehydrogenation treatment is required before finishing, and the process parameters of the complete dehydrogenation treatment are as follows: keeping the temperature at 850 ℃ for 1-10h under the vacuum condition of 650-.

9. The high-compactness industrial pure titanium part is characterized by being prepared by the powder metallurgy mold filling manufacturing method of any one of claims 1 to 8, and the prepared industrial pure titanium part has the relative density of more than or equal to 98.5 percent, the tensile strength of 600-800MPa and the elongation of 15-25 percent.

10. The high-density Ti-6Al-4V titanium alloy part is characterized by being prepared by the powder metallurgy mold filling manufacturing method of any one of claims 1 to 8, the relative density of the prepared Ti-6Al-4V titanium alloy part is more than or equal to 98.5 percent, the tensile strength is 900-1200MPa, and the elongation is 10-20 percent.

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