A kind of continuous carbon fibre strengthens liquid near-net-shape method and the device of aluminium base multiple materialTechnical field
The invention belongs to the liquid near-net-shape of high-performance metal based composites field, specifically relate to liquid near-net-shape method and device that a kind of continuous carbon fibre strengthens aluminium base multiple material.
Background technology
The continuous reinforced aluminum matrix composites of carbon fiber has excellent mechanics and physicals, at new and high technology engineering fields such as aerospace and advanced weaponries, be with a wide range of applications, the main preparation method of this matrix material has at present: solid-state High temperature diffusion connection method, squeeze casting method, vacuum suction casting technique and vacuum pressure infiltration method.Wherein, the advantage such as that High temperature diffusion connection method has is little to fibre-tendering, matrix material designability is strong, shortcoming is: complex technical process, production cost are high; Squeeze casting method has that composite pressure is high, Liquid Infiltration is complete, can eliminate the defects such as hole and shrinkage cavity, improves the advantages such as composite materials property, but shortcoming is: foundry goods shape is restricted, be difficult to realize near-net-shape, under high pressure, easily make the impaired cracking of precast body and produce casting flaw; The generation of the casting flaw such as vacuum suction casting technique can reduce bubble in matrix material, be mingled with, vacuum environment also can be avoided aluminium liquid and fiber oxidation, but shortcoming is: the wettability of fiber and aluminium liquid is poor, and high temperature aluminum liquid easily and between fiber serious surface reaction occurs and damaged composite material performance.The advantage of vacuum pressure infiltration method is: preparation technology is simple, can prepare complex-shaped composite material parts, realize the near-net-shape of matrix material, but its shortcoming is: infiltration temperature is higher, easily cause matrix alloy to react with carbon fiber, need carry out surface modification to improve the wetting property of itself and aluminum melt and to control surface reaction to carbon fiber.
Above preparation method respectively has feature, generally speaking, preparation for continuous fibre reinforced aluminum matrix composites, vacuum pressure infiltration method has preparation technology is simple, pressure is easily controlled, be difficult for causing precast body deformation and failure, can realize the advantages such as near-net-shape, is therefore suitable for the high complex precise part of manufacturing property requirement.In order to solve the low wetting property of carbon fiber and aluminum melt in vacuum pressure infiltration and to control the surface reaction problem between the two, generally need carry out surface modification treatment to carbon fiber, it is a kind of comparatively ideal carbon fiber surface modification method that plating nickel on surface is processed.But in current carbon fiber reinforced aluminum matrix composite vacuum pressure infiltration technique, there are following two deficiencies: surface oxidation and scaling loss that (1) nickel-coated carbon fibers is hankered in advance, not only damaged the performance of fiber own, and can reduce the wettability of itself and aluminium liquid, cause low pressure infiltration preparation difficulty; (2) nickel-coated carbon fibers and aluminium liquid high temperature are longer lower duration of contact, and serious surface reaction can occur, and not only damage the integrity of fiber own and performance, and easily generate a large amount of interfacial brittle phases, thereby worsen composite materials property.
summary of the invention:
First object of the present invention is to provide a kind of continuous carbon fibre to strengthen the liquid near-net-shape method (that is: vacuum aided pressure regulation infiltration casting method) of aluminium base multiple material, it has solved the damage of carbon fiber surface high temperature oxidation and surface reaction is controlled this two difficult problems, contribute to improve microstructure of composite density and integrity, improve composite materials property, and reduce its preparation cost, for technical foundation is established in the liquid near-net-shape preparation of the continuous reinforced aluminum matrix composites of high-performance carbon fibre.
Second object of the present invention is to provide a kind of continuous carbon fibre to strengthen the liquid near-net-shape device (that is: vacuum aided pressure regulation infiltration casting device) of aluminium base multiple material.
First object of the present invention is achieved in that
A liquid near-net-shape method that strengthens aluminium base multiple material, feature is: step is as follows:
A, according to the requirement of fiber volume fraction 35%-55%, prepare continuous carbon fibre precast body, quantitatively cut aluminum alloy ingot and obtain aluminum matrix alloy, carbon fabric perform and aluminum matrix alloy are respectively charged in casting mold and crucible in, whole device is connected to the laggard row airtight test of sealing;
B, fiber preheating and alloy melting: open crucible heater and casting mold well heater and carry out aluminium alloy smelting and carbon fiber preheating simultaneously, open vacuum pump valve and casting mold valve, crucible and casting mold are vacuumized and are kept simultaneously the air pressure balance of the two, after reaching 5-10Pa, the vacuum tightness of crucible tracheal pressure table and casting mold tracheal pressure table stops vacuumizing, close vacuum pump valve, open argon gas valve and pass into highly purified argon gas in crucible and casting mold, the argon pressure of crucible tracheal pressure table and casting mold tracheal pressure table reaches after 20-30KPa, close argon gas valve and keep pressure 10-20 minute, open vacuum pump valve and be evacuated to vacuum tightness 5-10Pa, then close vacuum pump valve, open argon gas valve and pass into argon gas pressurize, after 20-30KPa, close argon gas valve and keep pressure 10-20 minute, repeat above step, by vacuumizing and the hocketing of logical argon gas, realize alloy melting and fiber preheating under hypoxic atmosphere, until alloy melting and fiber preheating finish, by crucible thermopair, control the smelting temperature 650-800 ℃ of aluminium alloy, by casting mold thermopair, control the preheating temperature 400-650 ℃ of carbon fiber,
C, vacuum aided gas pressure infiltration: aluminium alloy is heated to the above 50-100 ℃ of liquidus temperature, carbon fabric perform is heated to 400-650 ℃, the two was all incubated after 1 hour, closing crucible well heater and casting mold well heater, close argon gas valve, opens vacuum pump valve, crucible and casting mold are vacuumized simultaneously, keep the two identical environment vacuum tightness, the vacuum tightness of crucible tracheal pressure table and casting mold tracheal pressure table, to 5-10Pa, is closed vacuum pump valve and casting mold valve; Open argon gas valve, molten aluminium liquid level in crucible is passed into the argon gas that pressure is 200-500KPa, under the differential pressure action of crucible and casting mold, make high temperature aluminum liquid with controlled pressure permeation in the carbon fabric perform in casting mold and the space of filling carbon fiber, realize the compound of aluminium alloy and carbon fiber, complete the vacuum aided low pressure infiltration of matrix material;
D, High Pressure Solidification is shaped: the temperature variation that embeds the casting mold thermopair in mould wall by several is monitored the temperature variation of mould wall in vacuum low-pressure infiltration process, after low pressure infiltration finishes, regulate argon gas valve, the argon pressure that makes to act on the molten aluminium liquid level in crucible rises to 800-1000KPa, remove casting mold well heater simultaneously and open cooling water valve, in watercooling jacket, pass into water coolant, by watercooling jacket, the composite castings in casting mold is carried out cooling fast, by casting mold thermocouple monitoring composite castings rate of cooling, by regulating the speed of cooling of the flow control composite castings of cooling-water pump, control the surface reaction degree between carbon fiber and aluminium alloy,
E, composite castings are cooled to after room temperature, open the bolt that is tightly connected between casting mold and casting mold tracheae, watercooling jacket, riser pipe, take off the casting mold demoulding, obtain continuous carbon fibre reinforced aluminum matrix composites foundry goods.
In step B, the mode hocketing by vacuumizing and pass into high-purity argon gas, controls the oxygen level in crucible and casting mold, realizes the protection to nickel-coated carbon fibers under high temperature.
Second object of the present invention is achieved in that
A kind of continuous carbon fibre strengthens the liquid near-net-shape device of aluminium base multiple material, feature is: comprise crucible and casting mold, at the interior outer wall that the crucible of aluminium alloy is housed, be surrounded by crucible heater, top at crucible is fixed with seal cover board, and the detecting end of crucible thermopair is embedded in the wall of crucible through after crucible heater from outside to inside, casting mold well heater is arranged on above the seal cover board of crucible, the casting mold that carbon fabric perform is inside housed is seated in casting mold well heater, outer wall at casting mold is wound with watercooling jacket, one end of watercooling jacket is connected with cyclic water tank, the other end of watercooling jacket is connected with the cooling-water pump with cooling water valve, and the detecting end that is several casting mold thermopairs that are arranged in parallel up and down is all embedded in the wall of casting mold through after casting mold well heater from outside to inside, with one end of the crucible tracheae of crucible tracheal pressure table, through the seal cover board of crucible, extend in crucible downwards, the other end of crucible tracheae is connected with first interface of four-way pipe connecting, the suction end of vacuum pump is connected with second interface of four-way pipe connecting by vacuum pump valve, the outlet side of argon tanks is connected with the 3rd interface of four-way pipe connecting by argon gas valve, one end with the casting mold tracheae of casting mold tracheal pressure table extend in crucible downwards, the other end of casting mold tracheae is connected with the 4th interface of four-way pipe connecting with after the series connection of casting mold valve, the upper end of riser pipe is connected with the bottom of casting mold, the seal cover board that the lower end of riser pipe is passed down through crucible extend in the aluminium liquid in crucible.
The present invention compares with traditional carbon fiber reinforced aluminum matrix composite preparation method, and the feature of the method applied in the present invention and device is: (1) has realized the hypoxemia temperature control preheating of nickel-coated carbon fibers; (2) low pressure infiltration and the High Pressure Solidification preparation of aluminum matrix composite have been realized; (3) speed of cooling having realized during composite castings solidifies is controlled.Surface reaction problem when the precast body distortion when oxidization burning loss while the invention solves carbon fiber preheating, infiltration and composite material solidification.
The pre-hot atmosphere control of carbon fiber and the control of composite castings process of cooling have been realized.Pre-hot atmosphere is controlled and has been avoided on the one hand the oxidation ablation under high temperature in carbon fiber warm, guaranteed the integrity of carbon fiber itself, avoid its mechanical property damage, protected on the other hand carbon fiber surface nickel coating integrity, improve wetting property between carbon fiber and molten aluminium, reduce Liquid Infiltration resistance, reduce fiber segregation and precast body distortion; Composite cools down process control can suppress surface reaction excessive between C/Al, reduces the damage to carbon fiber, controls interface A l4c3the quantity of fragility phase and pattern, contribute to improve composite materials property.In addition, improve composite cools down speed and be conducive to its matrix of refinement, further improve composite materials property.
Adopting present method and device to prepare continuous carbon fibre reinforced aluminum matrix composites, to have processing parameter controlled, technique integrated level height and the low advantage of cost, composite castings has good dense structure's property and mechanical property simultaneously, can solve the liquid near-net-shape technical barrier of continuous filament reinforced metallic matrix composite in engineering Application Areas.
accompanying drawing explanation
Fig. 1 is structural representation of the present invention;
Fig. 2 is unidirectional continuous enhancing Cfthe schematic diagram of/Al composite product;
Fig. 3 is unidirectional continuous enhancing Cfthe microcosmic schematic diagram of/Al microstructure of composite pattern, wherein:(a), vertical fibers bundle; (b) parallel fibers bundle;
Fig. 4 is that three-dimensional four-way strengthens C continuouslyfthe schematic diagram of/Al microstructure of composite pattern.
embodiment:
Below in conjunction with embodiment, method of the present invention is further detailed.
A liquid near-net-shape method that strengthens aluminium base multiple material, step is as follows:
A, according to the requirement of fiber volume fraction 35%-55%, prepare continuous carbon fibre precast body, quantitatively cut aluminum alloy ingot and obtain aluminum matrix alloy, carbon fabric perform and aluminum matrix alloy are respectively charged in casting mold and crucible in, whole device is connected to the laggard row airtight test of sealing;
B, fiber preheating and alloy melting: open crucible heater and casting mold well heater and carry out aluminium alloy smelting and carbon fiber preheating simultaneously, open vacuum pump valve and casting mold valve, crucible and casting mold are vacuumized and are kept simultaneously the air pressure balance of the two, after reaching 5-10Pa, the vacuum tightness of crucible tracheal pressure table and casting mold tracheal pressure table stops vacuumizing, close vacuum pump valve, open argon gas valve and pass into highly purified argon gas in crucible and casting mold, the argon pressure of crucible tracheal pressure table and casting mold tracheal pressure table reaches after 20-30KPa, close argon gas valve and keep pressure 10-20 minute, open vacuum pump valve and be evacuated to vacuum tightness 5-10Pa, then close vacuum pump valve, open argon gas valve and pass into argon gas pressurize, after 20-30KPa, close argon gas valve and keep pressure 10-20 minute, repeat above step, by vacuumizing and the hocketing of logical argon gas, realize alloy melting and fiber preheating under hypoxic atmosphere, until alloy melting and fiber preheating finish, by crucible thermopair, control the smelting temperature 650-800 ℃ of aluminium alloy, by casting mold thermopair, control the preheating temperature 400-650 ℃ of carbon fiber,
C, vacuum aided gas pressure infiltration: aluminium alloy is heated to the above 50-100 ℃ of liquidus temperature, carbon fabric perform is heated to 400-650 ℃, the two was all incubated after 1 hour, closing crucible well heater and casting mold well heater, close argon gas valve, opens vacuum pump valve, crucible and casting mold are vacuumized simultaneously, keep the two identical environment vacuum tightness, the vacuum tightness of crucible tracheal pressure table and casting mold tracheal pressure table, to 5-10Pa, is closed vacuum pump valve and casting mold valve; Open argon gas valve, molten aluminium liquid level in crucible is passed into the argon gas that pressure is 200-500KPa, under the differential pressure action of crucible and casting mold, make high temperature aluminum liquid with controlled pressure permeation in the carbon fabric perform in casting mold and the space of filling carbon fiber, realize the compound of aluminium alloy and carbon fiber, complete the vacuum aided low pressure infiltration of matrix material;
D, High Pressure Solidification is shaped: the temperature variation that embeds the casting mold thermopair in mould wall by several is monitored the temperature variation of mould wall in vacuum low-pressure infiltration process, after low pressure infiltration finishes, regulate argon gas valve, the argon pressure that makes to act on the molten aluminium liquid level in crucible rises to 800-1000KPa, remove casting mold well heater simultaneously and open cooling water valve, in watercooling jacket, pass into water coolant, by watercooling jacket, the composite castings in casting mold is carried out cooling fast, by casting mold thermocouple monitoring composite castings rate of cooling, by regulating the speed of cooling of the flow control composite castings of cooling-water pump, control the surface reaction degree between carbon fiber and aluminium alloy,
E, composite castings are cooled to after room temperature, open the bolt that is tightly connected between casting mold and casting mold tracheae, watercooling jacket, riser pipe, take off the casting mold demoulding, obtain continuous carbon fibre reinforced aluminum matrix composites foundry goods.
In step B, the mode hocketing by vacuumizing and pass into high-purity argon gas, controls the oxygen level in crucible and casting mold, realizes the protection to nickel-coated carbon fibers under high temperature.
A kind of continuous carbon fibre strengthens the liquid near-net-shape device of aluminium base multiple material, comprise crucible 15 and casting mold 22, at the interior outer wall that the crucible 15 of aluminium alloy is housed, be surrounded by crucible heater 18, top at crucible 15 is fixed with seal cover board 19, and the detecting end of crucible thermopair 16 is embedded in the wall of crucible 15 through after crucible heater 18 from outside to inside, casting mold well heater 23 is arranged on above the seal cover board 19 of crucible 15, the casting mold 22 that carbon fabric perform is inside housed is seated in casting mold well heater 23, outer wall at casting mold 22 is wound with watercooling jacket 24, one end of watercooling jacket 24 is connected with cyclic water tank 11, the other end of watercooling jacket 24 is connected with the cooling-water pump 8 with cooling water valve 21, and the detecting end that is three the casting mold thermopairs 12,13,14 that are arranged in parallel up and down is all embedded in the wall of casting mold 22 through after casting mold well heater 23 from outside to inside, seal cover board 19 with one end of the crucible tracheae 20 of crucible tracheal pressure table 7 through crucible 15 extend into downwards in crucible 15, the other end of crucible tracheae 20 is connected with first interface of four-way pipe connecting 4, the suction end of vacuum pump 6 is connected with second interface of four-way pipe connecting 4 by vacuum pump valve 5, the outlet side of argon tanks 1 is connected with the 3rd interface of four-way pipe connecting 4 by argon gas valve 2, one end with the casting mold tracheae 10 of casting mold tracheal pressure table 9 extend into downwards in casting mold 22, the other end of casting mold tracheae 10 is connected with the 4th interface of four-way pipe connecting 4 with after 3 series connection of casting mold tracheae valve, the upper end of riser pipe 17 is connected with the bottom of casting mold 22, the seal cover board 19 that the lower end of riser pipe 17 is passed down through crucible 15 extend in the aluminium liquid in crucible 15.Aluminium liquid in crucible 15 is entered in the fiber preform of casting mold 22 and is gone by riser pipe 17 under crucible-casting mold differential pressure action, regulates the air pressure in crucible 15 can complete low-pressure liquid infiltration and High Pressure Solidification forming process.
Embodiment 1:
Present embodiment is arranged in parallel and is inserted in silica tube by continuous carbon fibre, makes unidirectional fibre precast body, through vacuum aided pressure regulation infiltration casting near-net-shape, goes out unidirectional continuous enhancing Cf/ Al matrix material, carbon fiber volume fraction is 35%, aluminium alloy volume fraction is 65%.As shown in Figure 2, its microtexture as shown in Figure 3 for the continuous carbon fibre single-way reinforced aluminium base composite material goods of near-net-shape.
The nickel-coated carbon fibers T300 that selects 3K, aluminium alloy is selected ZL114A.
Embodiment 2:
Present embodiment is woven into precast body by continuous carbon fibre by three-dimensional four-way, goes out three-dimensional four-way strengthen continuously C through vacuum aided pressure regulation infiltration casting near-net-shapef/ Al matrix material, carbon fiber volume fraction is 45%, aluminium alloy volume fraction is 55%.Prepared matrix material microtexture as shown in Figure 4.
Embodiment 3:
Present embodiment is woven into precast body by continuous carbon fibre by three-dimensional four-way, through vacuum aided pressure regulation infiltration casting near-net-shape, goes out C/Al matrix material, and carbon fiber volume fraction is 55%, and aluminium alloy volume fraction is 45%.