A high-strength and high-toughness composite material for powder metallurgy and its preparation method

Abstract

This invention discloses a high-strength and tough composite material for powder metallurgy and its preparation method, belonging to the field of metal composite material technology. It addresses the technical problem that the toughness, strength, and wear resistance of existing high-strength and tough composite materials for powder metallurgy need further improvement. Specifically, it comprises the following components by weight: 86-90 parts copper powder, 2-4 parts nickel powder, 1.5-3 parts copper-tin composite, 1.5-3 parts tungsten-titanium composite, 1.5-3 parts reinforcing powder, 150-200 parts anhydrous ethanol, and 0.5-1 parts auxiliary additives. This invention further improves the toughness, strength, and wear resistance of the high-strength and tough composite material for powder metallurgy through the synergistic effect of the prepared copper-tin composite, tungsten-titanium composite, and reinforcing powder.

Description

Technical Field

[0001] This invention relates to the field of metal composite materials technology, and more specifically to a high-strength and high-toughness composite material for powder metallurgy and its preparation method. Background Technology

[0002] Powder metallurgy copper-based composites are widely used in machinery manufacturing, metallurgical equipment and other fields due to their good formability, excellent electrical and thermal conductivity and controllable cost. The synergistic improvement of their strength, toughness and wear resistance has become the core direction of industry research. Traditional technology often strengthens the copper matrix by adding a single ceramic phase or intermetallic compound, but there are problems such as poor bonding between the reinforcing phase and the matrix interface and uneven dispersion. Stress concentration is easily formed under stress, which leads to a decrease in material toughness and makes it difficult to achieve both high strength and high plasticity.

[0003] Some technologies have attempted to introduce multiphase reinforcements to improve the performance of copper-based composite materials. However, most of the reinforcing phases are simple physical mixtures without targeted modification based on their structural characteristics, which fails to create a synergistic strengthening effect. Furthermore, the high brittleness of ceramic reinforcing phases can lead to a significant deterioration in plasticity and toughness while improving wear resistance. Although metal reinforcing phases can improve plasticity, they are difficult to effectively improve wear resistance. In addition, in traditional preparation processes, the surface modification methods for reinforcing phases are limited, which can easily lead to secondary agglomeration, resulting in insufficient density of the composite material and further affecting its comprehensive mechanical properties. This makes it impossible to meet the integrated performance requirements of high strength, high toughness, and high wear resistance of powder metallurgy copper-based composite materials for high-end equipment.

[0004] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a high-strength and tough composite material for powder metallurgy and its preparation method, in order to solve the technical problem that the toughness, strength and wear resistance of high-strength and tough composite materials for powder metallurgy in the prior art need to be further improved.

[0006] The objective of this invention can be achieved through the following technical solution: a high-strength and high-toughness composite material for powder metallurgy, comprising the following components by weight: 86-90 parts copper powder, 2-4 parts nickel powder, 1.5-3 parts copper-tin composite, 1.5-3 parts tungsten-titanium composite, 1.5-3 parts reinforcing powder, 150-200 parts anhydrous ethanol and 0.5-1 parts auxiliary additives;

[0007] The auxiliary additives comprise the following components by weight: 0.4-0.6 parts zinc stearate and 0.1-0.3 parts boron powder.

[0008] Furthermore, the preparation method of the copper-tin composite is as follows: tin oxide powder is added to a reaction vessel containing deionized water and stirred for 10-20 minutes. Then, copper sulfate pentahydrate aqueous solution is added and stirred for another 20-30 minutes. Next, sodium hydroxide aqueous solution is added dropwise until the pH of the mixed solution reaches 7-8. After standing for 2-3 hours, the mixture is filtered. The filter cake is washed 3-4 times with deionized water and then 2-3 times with anhydrous ethanol. After filtration, the filter residue is placed in a crucible and then placed in a resistance furnace and heated at 550-570℃ for 2-3 hours. After cooling to room temperature, the mixture is ground and passed through a 300-mesh sieve to obtain the copper-tin composite.

[0009] Furthermore, the ratio of the tin oxide powder, deionized water, and copper sulfate pentahydrate aqueous solution is 11g:250mL:10-14mL, the mass fraction of the copper sulfate pentahydrate aqueous solution is 15.5%, and the mass fraction of the sodium hydroxide aqueous solution is 1.5%.

[0010] Furthermore, the preparation method of the tungsten-titanium composite is as follows: potassium chloride, sodium chloride, and calcium chloride are added to a reaction vessel and mixed evenly. Then, titanium hydride powder and tungsten powder are added and stirred for 20-30 minutes. The mixture is first placed in an alumina crucible and then placed in a tube furnace. It is then heated at 10°C / min under a nitrogen atmosphere. -1 The temperature was raised to 750-850℃ at a rate of [missing information], held at that temperature for 1.5-2.5 hours, and then cooled to room temperature in the furnace. The product was washed 3-4 times with deionized water, and then freeze-dried at -40-50℃ and 8-10Pa pressure for 6-8 hours. Then, it was sintered at 1200-1300℃ for 3-4 hours under a vacuum of 0.1Pa and a pressure of 30MPa. After sintering, the pressure was released and the product was cooled to room temperature in the furnace. The product was then ground and passed through a 300-mesh sieve to obtain the tungsten-titanium composite.

[0011] Furthermore, the ratio of potassium chloride, sodium chloride, calcium chloride, titanium hydride powder and tungsten powder is 4g:4g:2g:1-2g:6-8g.

[0012] Furthermore, the method for preparing the reinforcing powder is as follows:

[0013] A1. Add alumina ceramic particles and silicon carbide whiskers to a reaction vessel containing anhydrous ethanol, ultrasonically disperse for 30-50 min, then transfer to a vacuum drying oven and dry at 60°C to constant weight. Transfer the dried product to a ball mill for ball milling and pass through a 300-mesh sieve to obtain pretreated powder.

[0014] A2. Add the pretreated powder, wetting and dispersing agent BYK-103, trimethylolpropane triacrylate and 1,6-hexanediol diacrylate to a ball mill and ball mill for 10-12 hours. Then add the photoinitiator Irgacure-819 and continue ball milling for 1-2 hours. After vacuum degassing for 40-60 minutes, freeze dry at -30-40℃ for 8-10 hours. Remove, grind, and pass through a 300-mesh sieve to obtain the reinforced powder.

[0015] Further, in step A1, the principle ratio of the alumina ceramic particles, silicon carbide whiskers, and anhydrous ethanol is 10g:2-3g:100-140mL; in step A2, the dosage ratio of the pretreatment powder, wetting and dispersing agent BYK-103, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, and photoinitiator Irgacure-819 is 100g:4-6g:35-45g:10-12g:0.8-1g.

[0016] This invention also proposes a method for preparing a high-strength and high-toughness composite material for powder metallurgy, comprising the following steps:

[0017] S1. Add copper powder, nickel powder, copper-tin composite, tungsten-titanium composite, reinforcing powder and auxiliary additives together into a planetary ball mill, use anhydrous ethanol as solvent, and ball mill at a speed of 350-450 r / min for 8-10 h to obtain a uniformly dispersed mixed powder.

[0018] S2. Transfer the mixed powder to a vacuum drying oven and dry it to constant weight at 60-70℃ and a vacuum of 10-20Pa. After drying, grind it and pass it through a 300-mesh sieve. Then put it into a mold and cold press it at 20-30℃ and 300-400MPa to obtain a green body.

[0019] S3. Place the green billet in a tube furnace and heat it to 1150-1250℃ at a rate of 8-12℃·min-1 under a pure nitrogen atmosphere. Sinter at a constant temperature for 2-3 hours. After sintering, cool it to room temperature with the furnace at a rate of 5-8℃·min-1 to finally obtain a high-strength and tough composite material for powder metallurgy.

[0020] The present invention has the following beneficial effects:

[0021] 1. The copper-tin composite of the present invention has a core-shell structure of copper oxide coated with tin oxide. The fine spherical core-shell particles can hinder crack propagation through particle bridging and dislocation entanglement. The tungsten-titanium composite has a layered W-Ti intermetallic structure. The slip and separation between the layers can achieve crack passivation and deflection, consuming the energy of crack propagation. The reinforcing powder has an organically coated modified silicon carbide whisker-alumina particle dual-phase structure. The silicon carbide whiskers can play a major toughening role through the classic toughening mechanism of whisker pull-out and crack deflection. The alumina particles can form secondary toughening sites between the whiskers, further blocking the continuous propagation of cracks. The elemental composition of the three reinforcing phases is complementary and the structure is synergistic. The diffuse distribution of the copper-tin composite forms the initial obstacle to crack propagation. The layered structure of the tungsten-titanium composite achieves secondary deflection of cracks. The whisker-particle dual-phase structure of the reinforcing powder completes the final crack blocking. The three of them form a multi-level toughening system with the copper-nickel matrix, which significantly improves the overall toughness of the composite material.

[0022] 2. In the copper-tin composite of the present invention, a hard tin oxide core provides load support, and a soft copper oxide coating layer enhances the interfacial bonding force with the copper-nickel matrix, achieving dispersion strengthening while avoiding stress concentration. The layered W-Ti structure of the tungsten-titanium composite provides alloying strengthening for the composite material due to the high hardness of tungsten. Titanium forms a solid solution with the copper-nickel matrix to achieve solid solution strengthening. The layered structure can also refine the matrix grains through fine grain strengthening, improving the strength and plasticity of the matrix itself. After the reinforcing powder is modified by organic coating, the interfacial compatibility between silicon carbide / alumina and the matrix is ​​greatly improved. Whiskers and particles can effectively transfer the applied load, dispersing the stress borne by the matrix to the reinforcing phase, achieving load transfer strengthening. Moreover, the organic coating layer can buffer the interfacial stress and reduce the occurrence of brittle fracture. The three reinforcing phases achieve synergy from multiple dimensions of dispersion strengthening, solid solution alloying strengthening, and load transfer strengthening. At the same time, each special structure optimizes the interfacial bonding state with the matrix, effectively alleviating the deterioration of material plasticity by ceramic reinforcement while improving tensile strength, ensuring elongation after fracture, and achieving a synergistic improvement in strength and plasticity.

[0023] 3. In the copper-tin composite of the present invention, tin oxide possesses the characteristics of high hardness and high wear resistance. The copper oxide coating layer ensures its uniform dispersion within the copper-nickel matrix, forming numerous hard and wear-resistant sites that effectively resist cutting and scratching by abrasive particles, reducing matrix wear. The layered W-Ti structure of the tungsten-titanium composite, with tungsten exhibiting excellent wear resistance and deformation resistance, creates a wear-resistant layered barrier on the surface of the composite material. During abrasive action, only slight surface wear occurs, preventing deep erosion of the matrix. Simultaneously, the layered structure's resistance to plastic deformation reduces adhesive wear, enhancing the silicon carbide whisker-alumina particle dual-phase structure of the powder. Silicon carbide whiskers intertwine in the matrix to form a three-dimensional wear-resistant skeleton, effectively supporting the matrix and resisting the indentation and cutting of abrasive particles. Alumina particles fill the gaps between the whisker skeleton, filling the weak areas of wear resistance. Moreover, the organically coated and modified reinforcing phase is tightly bonded to the matrix, preventing the reinforcing phase from falling off under the action of abrasive particles and forming secondary abrasive particles, thus greatly reducing the degree of abrasive wear. Based on the wear-resistant properties of their own elements, the three reinforcing phases form a complementary wear-resistant system through the special structures of core-shell, layered, and whisker-particle, achieving synergy in resisting abrasive cutting, reducing adhesive wear, and building a wear-resistant skeleton, thereby greatly improving the overall wear resistance of the composite material. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In this application, the copper powder is selected from Hubei Chengfeng Chemical Co., Ltd., CAS No. 7440-50-8, with a mesh size of 300 mesh;

[0026] In this application, the nickel powder is selected from Tianjin Jinxin New Material Technology Co., Ltd., CAS No. 202502A0, with a mesh size of 300 mesh;

[0027] In this application, the titanium hydride powder is selected from Jinzhou Jinhe New Materials Co., Ltd., with a content of 99.6% and a mesh size of 300.

[0028] In this application, the tungsten powder is selected from Qinghe County Chaonai Metal Materials Co., Ltd., with a tungsten content of 99.99% and a mesh size of 300.

[0029] In this application, the alumina ceramic particles are selected from Zibo Dongyusheng Chemical Co., Ltd., with a particle size of 30nm and an effective component content of 99.99%.

[0030] In this application, the silicon carbide whiskers are selected from Qinghe County Chaotai Metal Materials Co., Ltd., CAS No. 1344-2-2, with a mesh size of 2000 mesh;

[0031] In this application, the wetting and dispersing agent BYK-103 is selected from Jining Fangyu Chemical Co., Ltd., with an effective ingredient content of 98% and the model BYK-103.

[0032] In this application, the photoinitiator Irgacure-819 is selected from Shanghai Longdi Chemical Co., Ltd., CAS No. 162881-26-7.

[0033] Example 1

[0034] This embodiment provides a method for preparing a high-strength and high-toughness composite material for powder metallurgy, including the following steps:

[0035] S1. Preparation of copper-tin composite

[0036] Weigh 22g of tin oxide powder and add it to a reaction vessel containing 500mL of deionized water. Stir for 10min. Then add 20mL of 15.5wt% copper sulfate pentahydrate aqueous solution and continue stirring for 20min. Then add 1.5wt% sodium hydroxide aqueous solution dropwise until the pH of the mixed solution reaches 7. After standing for 2h, filter. Wash the filter cake three times with deionized water and twice with anhydrous ethanol. Filter again. Place the filter residue in a crucible and then place it in a resistance furnace. Heat at 550℃ for 2h. Remove and cool to room temperature. Grind and pass through a 300-mesh sieve to obtain a copper-tin composite.

[0037] During the reaction, in the aqueous system, copper ions provided by copper sulfate pentahydrate adsorb onto the surface of tin oxide particles. Sodium hydroxide aqueous solution is added dropwise to maintain the pH of the system at a weakly alkaline level. Copper ions react with hydroxide ions to form copper hydroxide precipitate, which uniformly coats the surface of tin oxide particles, forming a core-shell structure precursor. After settling, filtration, and washing to remove impurity ions, the copper hydroxide is calcined to decompose into copper oxide, ultimately yielding a composite powder of copper oxide uniformly coated with tin oxide.

[0038] S2, Preparation of tungsten-titanium composite

[0039] Weigh out 8g of potassium chloride, 8g of sodium chloride, and 4g of calcium chloride and add them to the reaction vessel. Mix them thoroughly. Then add 2g of titanium hydride powder and 12g of tungsten powder. Stir for 20 minutes, then transfer the mixture to an alumina crucible and place it in a tube furnace. Stir at 10°C / min under a nitrogen atmosphere. -1The temperature was raised to 750℃ at a certain rate, held at that temperature for 1.5 hours, and then cooled to room temperature in the furnace. The product was washed three times with deionized water and then freeze-dried at -40℃ and 8Pa for 6 hours. Then, it was sintered at 1200℃ for 3 hours under a vacuum of 0.1Pa and a pressure of 30MPa. After sintering, the pressure was released and the product was cooled to room temperature in the furnace. The product was then ground and passed through a 300-mesh sieve to obtain the tungsten-titanium composite.

[0040] During the reaction, under high temperature conditions, the potassium chloride-sodium chloride-calcium chloride ternary mixed molten salt system is in a molten state. Titanium hydride decomposes upon heating to generate highly active elemental titanium and release hydrogen gas. The active titanium is uniformly attached to the surface of tungsten particles under the coating and dispersion of molten salt. After washing and freeze-drying, the material is sintered under high temperature and high pressure under vacuum conditions. Titanium and tungsten atoms undergo significant interfacial diffusion and metallurgical bonding to form a stable tungsten-titanium alloy interface and layered structure. Finally, the layered tungsten-titanium composite is obtained by grinding and sieving.

[0041] S3, Preparation of reinforced powder

[0042] Weigh 100g of alumina ceramic particles and 20g of silicon carbide whiskers and add them to a reaction vessel containing 1000mL of anhydrous ethanol. After ultrasonic dispersion for 30min, transfer the mixture to a vacuum drying oven and dry it at 60℃ to constant weight. Transfer the dried product to a ball mill and ball mill it. Pass it through a 300-mesh sieve to obtain the pretreated powder.

[0043] Weigh out 100g of pretreated powder, 4g of wetting and dispersing agent BYK-103, 35g of trimethylolpropane triacrylate and 10g of 1,6-hexanediol diacrylate, and add them to a ball mill and ball mill for 10 hours. Then add 0.8g of photoinitiator Irgacure-819 and continue ball milling for 1 hour. After vacuum degassing for 40 minutes, freeze dry at -30°C for 8 hours, take out and grind, and pass through a 300-mesh sieve to obtain reinforced powder.

[0044] In the reaction process, alumina ceramic particles and silicon carbide whiskers are first added to anhydrous ethanol and ultrasonically dispersed to break up powder agglomerates, so that the two ceramic powders are uniformly dispersed in the ethanol medium. Then, after vacuum drying and ball milling, a uniformly dispersed pretreated powder is obtained. Next, it is ball-milled together with organic materials. The wetting and dispersing agent BYK-103 is adsorbed on the surface of alumina particles and silicon carbide, reducing the surface tension of the powder, improving its wettability and dispersibility in the organic monomer, and inhibiting secondary agglomeration of the powder. At the same time, the mechanical force during ball milling makes the alumina particles and silicon carbide fully mixed, and the organic monomer is uniformly coated on the powder surface to form an organic coating layer. After adding the photoinitiator Irgacure-819, ball milling is continued to ensure that the photoinitiator is uniformly dispersed in the system and that the premature initiation reaction does not occur. After vacuum degassing, freeze drying, grinding and sieving, the reinforced powder is obtained.

[0045] S4. Preparation of mixed powder

[0046] Weigh out 0.4 parts by weight of zinc stearate and 0.1 parts by weight of boron powder, mix them evenly, and obtain the auxiliary additive;

[0047] Weigh out 86 parts copper powder, 2 parts nickel powder, 1.5 parts copper-tin composite, 1.5 parts tungsten-titanium composite, 1.5 parts reinforcing powder and 0.5 parts auxiliary additives by weight, add them together to a planetary ball mill, use 150 parts anhydrous ethanol as solvent, and ball mill at 350 r / min for 8 hours to obtain a uniformly dispersed mixed powder.

[0048] S5. Preparation of high-strength and tough composite materials for powder metallurgy

[0049] The mixed powder was transferred to a vacuum drying oven and dried to constant weight at 60°C and 10 Pa. After being removed, it was ground and passed through a 300-mesh sieve. Then it was placed into a mold and cold-pressed at 20°C and 300 MPa to obtain a green body.

[0050] The green billet was placed in a tube furnace and heated at 8°C / min under a pure nitrogen atmosphere. -1 The temperature was increased to 1150℃ at a rate of [missing information], and sintered at a constant temperature for 2 hours. After sintering, the temperature was increased to [missing information] at a rate of 5℃·min [missing information]. -1 The furnace is cooled to room temperature at a certain rate, and finally a high-strength and tough composite material for powder metallurgy is obtained.

[0051] Example 2

[0052] This embodiment provides a method for preparing a high-strength and high-toughness composite material for powder metallurgy, including the following steps:

[0053] S1. Preparation of copper-tin composite

[0054] Weigh 22g of tin oxide powder and add it to a reaction vessel containing 500mL of deionized water. Stir for 15min. Then add 24mL of 15.5wt% copper sulfate pentahydrate aqueous solution and continue stirring for 25min. Then add 1.5wt% sodium hydroxide aqueous solution dropwise until the pH of the mixed solution reaches 7.5. After standing for 2.5h, filter. Wash the filter cake three times with deionized water and twice with anhydrous ethanol. Filter again. Place the filter residue in a crucible and then place it in a resistance furnace. Heat at 560℃ for 2.5h. Remove and cool to room temperature. Grind and pass through a 300-mesh sieve to obtain a copper-tin composite.

[0055] S2, Preparation of tungsten-titanium composite

[0056] Weigh out 8g of potassium chloride, 8g of sodium chloride, and 4g of calcium chloride and add them to the reaction vessel. Mix them thoroughly. Then add 3g of titanium hydride powder and 14g of tungsten powder. Stir for 25 minutes, then transfer the mixture to an alumina crucible and place it in a tube furnace. Stir at 10°C / min under a nitrogen atmosphere. -1 The temperature was raised to 800℃ at a certain rate, held at that temperature for 2 hours, and then cooled to room temperature in the furnace. The product was washed three times with deionized water and then freeze-dried at -45℃ and 9Pa pressure for 7 hours. Then, it was sintered at 1250℃ for 3.5 hours under a vacuum of 0.1Pa and a pressure of 30MPa. After sintering, the pressure was released and the product was cooled to room temperature in the furnace. The product was then ground and passed through a 300-mesh sieve to obtain the tungsten-titanium composite.

[0057] S3, Preparation of reinforced powder

[0058] Weigh 100g of alumina ceramic particles and 25g of silicon carbide whiskers and add them to a reaction vessel containing 1200mL of anhydrous ethanol. After ultrasonic dispersion for 40min, transfer the mixture to a vacuum drying oven and dry it at 60℃ to constant weight. Transfer the dried product to a ball mill and ball mill it. Pass it through a 300-mesh sieve to obtain the pretreated powder.

[0059] Weigh out 100g of pretreated powder, 5g of wetting and dispersing agent BYK-103, 40g of trimethylolpropane triacrylate and 11g of 1,6-hexanediol diacrylate, and add them to a ball mill and ball mill for 11 hours. Then add 0.9g of photoinitiator Irgacure-819 and continue ball milling for 1.5 hours. After vacuum degassing for 50 minutes, freeze dry at -35°C for 9 hours, take out and grind, and pass through a 300-mesh sieve to obtain reinforced powder.

[0060] S4. Preparation of mixed powder

[0061] Weigh out 0.5 parts by weight of zinc stearate and 0.2 parts by weight of boron powder, mix them evenly, and obtain the auxiliary additive;

[0062] Weigh out 88 parts copper powder, 3 parts nickel powder, 2.2 parts copper-tin composite, 2.2 parts tungsten-titanium composite, 2.2 parts reinforcing powder, and 0.7 parts auxiliary additives by weight and add them to a planetary ball mill. Use 170 parts anhydrous ethanol as solvent and ball mill at 400 r / min for 9 hours to obtain a uniformly dispersed mixed powder.

[0063] S5. Preparation of high-strength and tough composite materials for powder metallurgy

[0064] The mixed powder was transferred to a vacuum drying oven and dried to constant weight at 65°C and 15 Pa. After being removed, it was ground and passed through a 300-mesh sieve. Then it was placed into a mold and cold-pressed at 25°C and 350 MPa to obtain a green body.

[0065] The green billet was placed in a tube furnace and heated at 10°C / min under a pure nitrogen atmosphere. -1 The temperature was increased to 1200℃ at a rate of [missing information], and sintered at a constant temperature for 2.5 hours. After sintering, the temperature was increased to 6.5℃·min [missing information]. -1 The furnace is cooled to room temperature at a certain rate, and finally a high-strength and tough composite material for powder metallurgy is obtained.

[0066] Example 3

[0067] This embodiment provides a method for preparing a high-strength and high-toughness composite material for powder metallurgy, including the following steps:

[0068] S1. Preparation of copper-tin composite

[0069] Weigh 22g of tin oxide powder and add it to a reaction vessel containing 500mL of deionized water. Stir for 20min. Then add 28mL of 15.5wt% copper sulfate pentahydrate aqueous solution and continue stirring for 30min. Then add 1.5wt% sodium hydroxide aqueous solution dropwise until the pH of the mixed solution reaches 8. After standing for 3h, filter. Wash the filter cake 4 times with deionized water and 3 times with anhydrous ethanol. Filter again. Place the filter residue in a crucible and place it in a resistance furnace. Heat at 570℃ for 3h. Remove and cool to room temperature. Grind and pass through a 300-mesh sieve to obtain a copper-tin composite.

[0070] S2, Preparation of tungsten-titanium composite

[0071] Weigh out 8g of potassium chloride, 8g of sodium chloride, and 4g of calcium chloride and add them to the reaction vessel. Mix them thoroughly. Then add 4g of titanium hydride powder and 16g of tungsten powder. Stir for 30 minutes, then transfer the mixture to an alumina crucible and place it in a tube furnace. Stir at 10°C / min under a nitrogen atmosphere. -1 The temperature was raised to 850℃ at a certain rate, held at that temperature for 2.5 hours, and then cooled to room temperature in the furnace. The product was washed four times with deionized water and then freeze-dried at -50℃ and 10Pa for 8 hours. Then, it was sintered at 1300℃ for 4 hours under a vacuum of 0.1Pa and a pressure of 30MPa. After sintering, the pressure was released and the product was cooled to room temperature in the furnace. The product was then ground and passed through a 300-mesh sieve to obtain the tungsten-titanium composite.

[0072] S3, Preparation of reinforced powder

[0073] Weigh 100g of alumina ceramic particles and 30g of silicon carbide whiskers and add them to a reaction vessel containing 1400mL of anhydrous ethanol. After ultrasonic dispersion for 50min, transfer the mixture to a vacuum drying oven and dry it at 60℃ to constant weight. Transfer the dried product to a ball mill and ball mill it. Pass it through a 300-mesh sieve to obtain the pretreated powder.

[0074] Weigh out 100g of pretreated powder, 6g of wetting and dispersing agent BYK-103, 45g of trimethylolpropane triacrylate and 12g of 1,6-hexanediol diacrylate, and add them to a ball mill and ball mill for 12 hours. Then add 1g of photoinitiator Irgacure-819 and continue ball milling for 2 hours. After vacuum degassing for 60 minutes, freeze dry at -40°C for 10 hours, take out and grind, and pass through a 300-mesh sieve to obtain reinforced powder.

[0075] S4. Preparation of mixed powder

[0076] Weigh out 0.6 parts by weight of zinc stearate and 0.3 parts by weight of boron powder, mix them evenly, and obtain the auxiliary additive;

[0077] Weigh out 90 parts copper powder, 4 parts nickel powder, 3 parts copper-tin composite, 3 parts tungsten-titanium composite, 3 parts reinforcing powder and 1 part auxiliary additive by weight and add them together into a planetary ball mill. Use 200 parts anhydrous ethanol as solvent and ball mill at 450 r / min for 10 h to obtain a uniformly dispersed mixed powder.

[0078] S5. Preparation of high-strength and tough composite materials for powder metallurgy

[0079] The mixed powder was transferred to a vacuum drying oven and dried to constant weight at 70°C and 20 Pa. After being removed, it was ground and passed through a 300-mesh sieve. Then it was placed into a mold and cold-pressed at 30°C and 400 MPa to obtain a green body.

[0080] The green billet was placed in a tube furnace and heated at 12°C / min under a pure nitrogen atmosphere. -1 The temperature was increased to 1250℃ at a rate of [missing information], and sintered at a constant temperature for 3 hours. After sintering, the temperature was increased to 8℃·min [missing information]. -1 The furnace is cooled to room temperature at a certain rate, and finally a high-strength and tough composite material for powder metallurgy is obtained.

[0081] Comparative Example 1

[0082] The difference between this comparative example and Example 3 is that step S1 is omitted, and copper-tin complex in step S4 is replaced with copper sulfate pentahydrate in step S1.

[0083] Comparative Example 2

[0084] The difference between this comparative example and Example 3 is that step S2 is omitted, and the tungsten-titanium composite in step S4 is replaced with titanium hydride powder in step S2.

[0085] Comparative Example 3

[0086] The difference between this comparative example and Example 3 is that step S3 is omitted, and the reinforcing powder in step S4 is replaced with silicon carbide whiskers from step S3.

[0087] Performance testing:

[0088] The plane strain fracture toughness of the high-strength and high-toughness composite materials for powder metallurgy prepared by Examples 1-3 and Comparative Examples 1-3 was tested according to the standard GB / T 4161-2007 "Test Method for Plane Strain Fracture Toughness of Metallic Materials" to represent the toughness of the high-strength and high-toughness composite materials for powder metallurgy.

[0089] The elongation after fracture and tensile strength of the high-strength and tough composite materials for powder metallurgy prepared by Examples 1-3 and Comparative Examples 1-3 were tested in accordance with the standard GB / T 228.1-2021 "Metallic materials - Tensile testing - Part 1: Test method at room temperature".

[0090] The volumetric wear of the high-strength and tough composite materials for powder metallurgy prepared in Examples 1-3 and Comparative Examples 1-3 was tested according to the standard GB / T 12444-2006 "Test Methods for Wear of Metallic Materials - Ring-Block Sliding Wear Test". This test was used to represent the wear resistance of the high-strength and tough composite materials for powder metallurgy. The specific test results are shown in Table 1 below:

[0091] Table 1 - Performance Test Data of Samples

[0092] Group Project <![CDATA[Plane strain fracture toughness (MPa·m 1 / 2 ).]]> Elongation after fracture (%) Tensile strength (MPa) <![CDATA[Volume wear (mm 3 )]]> 32-45 8-15 480-650 0.08-0.2 Example 1 41.6 13.9 572 0.101 Example 2 41.9 14.1 580 0.095 Example 3 42.3 14.4 586 0.086 Comparative Example 1 38.9 12.8 527 0.357 Comparative Example 2 36.4 12.1 498 0.276 Comparative Example 3 33.4 10.9 457 0.214

[0093] Data Analysis:

[0094] Comparative analysis of the data in Table 1 above shows that the plane strain fracture toughness of the high-strength and tough composite material for powder metallurgy prepared in this invention is measured to be MPa·m. 1 / 2 The elongation after fracture was %, the tensile strength was MPa, and the volumetric wear was mm. 3 ;

[0095] Comparative Example 1, in which copper oxide was coated with copper oxide instead of copper sulfate pentahydrate, lacked the dispersion toughening and interface optimization effects of the core-shell structure, resulting in a significant reduction in crack propagation inhibition and a decrease in its plane strain fracture toughness to 38.9 MPa·m. 1 / 2 Simultaneously, without the load support and interface buffer of the core-shell structure, the tensile strength drops to 527 MPa, the elongation after fracture drops to 12.8%, and the uniform dispersion of the tin oxide hard wear-resistant sites is lost, resulting in a volumetric wear rate of 0.357 mm. 3 ;

[0096] Comparative Example 2 uses titanium hydride powder to replace the layered W-Ti tungsten-titanium composite. Without the crack passivation, grain refinement, and alloying strengthening effects of the layered structure, cracks propagate rapidly, and the matrix strength is insufficiently improved, resulting in a plane strain fracture toughness of 36.4 MPa·m. 1 / 2The tensile strength is 498 MPa and the elongation after fracture is 12.1%. However, due to the loss of the layered wear-resistant barrier of tungsten, the volumetric wear increases to 0.276 mm. 3 ;

[0097] Comparative Example 3 uses silicon carbide whiskers to replace organically coated silicon carbide / alumina reinforcing powder. This results in the loss of whisker-particle dual-phase toughening, load transfer, and three-dimensional wear-resistant framework functions. Furthermore, the unmodified whiskers are prone to agglomeration, causing stress concentration, leading to a plane strain fracture toughness of only 33.4 MPa·m. 1 / 2 The toughness deterioration was most significant; the tensile strength was 457 MPa and the elongation after fracture was 10.9%. Although silicon carbide whiskers have a certain wear resistance, the lack of alumina particles to fill weak areas resulted in a volumetric wear rate of 0.214 mm. 3 .

[0098] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-strength and high-toughness composite material for powder metallurgy, characterized in that, It comprises the following components by weight: 86-90 parts copper powder, 2-4 parts nickel powder, 1.5-3 parts copper-tin composite, 1.5-3 parts tungsten-titanium composite, 1.5-3 parts reinforcing powder, 150-200 parts anhydrous ethanol and 0.5-1 parts auxiliary additives; The auxiliary additives comprise the following components by weight: 0.4-0.6 parts zinc stearate and 0.1-0.3 parts boron powder.

2. The high-strength and high-toughness composite material for powder metallurgy according to claim 1, characterized in that, The preparation method of the copper-tin composite is as follows: Tin oxide powder is added to a reaction vessel containing deionized water and stirred for 10-20 minutes. Then, copper sulfate pentahydrate aqueous solution is added and stirred for another 20-30 minutes. Sodium hydroxide aqueous solution is then added dropwise until the pH of the mixed solution reaches 7-8. After standing for 2-3 hours, the mixture is filtered. The filter cake is washed 3-4 times with deionized water and then 2-3 times with anhydrous ethanol. After filtration, the filter residue is placed in a crucible and then placed in a resistance furnace and heated at 550-570℃ for 2-3 hours. After cooling to room temperature, the mixture is ground and passed through a 300-mesh sieve to obtain the copper-tin composite.

3. A high-strength and high-toughness composite material for powder metallurgy according to claim 2, characterized in that, The ratio of tin oxide powder, deionized water, and copper sulfate pentahydrate aqueous solution is 11g:250mL:10-14mL, the copper sulfate pentahydrate aqueous solution has a mass fraction of 15.5%, and the sodium hydroxide aqueous solution has a mass fraction of 1.5%.

4. A high-strength and high-toughness composite material for powder metallurgy according to claim 1, characterized in that, The preparation method of the tungsten-titanium composite is as follows: potassium chloride, sodium chloride, and calcium chloride are added to a reaction vessel and mixed evenly. Then, titanium hydride powder and tungsten powder are added and stirred for 20-30 minutes. The mixture is first placed in an alumina crucible and then placed in a tube furnace. It is then heated at 10°C / min under a nitrogen atmosphere. -1 The temperature was raised to 750-850℃ at a rate of [missing information], held at that temperature for 1.5-2.5 hours, and then cooled to room temperature in the furnace. The product was washed 3-4 times with deionized water, and then freeze-dried at -40-50℃ and 8-10Pa pressure for 6-8 hours. Then, it was sintered at 1200-1300℃ for 3-4 hours under a vacuum of 0.1Pa and a pressure of 30MPa. After sintering, the pressure was released and the product was cooled to room temperature in the furnace. The product was then ground and passed through a 300-mesh sieve to obtain the tungsten-titanium composite.

5. A high-strength and high-toughness composite material for powder metallurgy according to claim 4, characterized in that, The ratio of potassium chloride, sodium chloride, calcium chloride, titanium hydride powder and tungsten powder is 4g:4g:2g:1-2g:6-8g.

6. A high-strength and high-toughness composite material for powder metallurgy according to claim 1, characterized in that, The method for preparing the reinforced powder is as follows: A1. Add alumina ceramic particles and silicon carbide whiskers to a reaction vessel containing anhydrous ethanol, ultrasonically disperse for 30-50 min, then transfer to a vacuum drying oven and dry at 60°C to constant weight. Transfer the dried product to a ball mill for ball milling and pass through a 300-mesh sieve to obtain pretreated powder. A2. Add the pretreated powder, wetting and dispersing agent BYK-103, trimethylolpropane triacrylate and 1,6-hexanediol diacrylate to a ball mill and ball mill for 10-12 hours. Then add the photoinitiator Irgacure-819 and continue ball milling for 1-2 hours. After vacuum degassing for 40-60 minutes, freeze dry at -30-40℃ for 8-10 hours. Remove, grind, and pass through a 300-mesh sieve to obtain the reinforced powder.

7. A high-strength and high-toughness composite material for powder metallurgy according to claim 6, characterized in that, In step A1, the principle ratio of the alumina ceramic particles, silicon carbide whiskers, and anhydrous ethanol is 10g:2-3g:100-140mL; in step A2, the dosage ratio of the pretreatment powder, wetting and dispersing agent BYK-103, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, and photoinitiator Irgacure-819 is 100g:4-6g:35-45g:10-12g:0.8-1g.

8. A method for preparing a high-strength and high-toughness composite material for powder metallurgy, applied to the high-strength and high-toughness composite material for powder metallurgy as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Add copper powder, nickel powder, copper-tin composite, tungsten-titanium composite, reinforcing powder and auxiliary additives together into a planetary ball mill, use anhydrous ethanol as solvent, and ball mill at a speed of 350-450 r / min for 8-10 h to obtain a uniformly dispersed mixed powder. S2. Transfer the mixed powder to a vacuum drying oven and dry it to constant weight at 60-70℃ and a vacuum of 10-20Pa. After drying, grind it and pass it through a 300-mesh sieve. Then put it into a mold and cold press it at 20-30℃ and 300-400MPa to obtain a green body. S3. Place the green billet in a tube furnace and heat it at 8-12℃·min under a pure nitrogen atmosphere. -1 The temperature is increased to 1150-1250℃ at a rate of [missing information], and sintered at a constant temperature for 2-3 hours. After sintering, the temperature is increased at 5-8℃ / min [missing information]. -1 The furnace is cooled to room temperature at a certain rate, and finally a high-strength and tough composite material for powder metallurgy is obtained.