Background technology
Aluminum matrix composite has specific tenacity, specific modulus height, high temperature resistant, wear-resistant and thermal expansivity is little, dimensional stabilizing etc. is excellent physicals and mechanical properties have a wide range of applications in industries such as aerospace, military and national defense field and automobile, electronic instrument.
Along with improving constantly of energy scarcity and car speed, energy-conservation with loss of weight is that the vehicle lightweight technological development of purpose receives much concern.Compare with the conventional steel iron material, particle enhanced aluminum-based composite material is because have higher specific tenacity, specific rigidity, and good thermostability and wear resistance are well suited for being used for making automobile and high-speed train braking system and retarding disc.Stopper is one of key part of vehicle, and the quality of its performance directly influences the quality of vehicle performance, and therefore, the design of stopper seems quite important in the car load design.As the generation of the friction brake of the important assurance of vehicle safety travel and development all the time with the automotive engineering interpromoting relation in five elements together, along with the continuous development of people's life idea and automotive engineering, huge variation has all taken place from structure to the material of forming friction pair in friction brake.The selected material of retarding disc influences bigger to braking effect, the unlike material of retarding disc, structure, metallographic structure all can produce bigger influence to the frictional behaviour of friction pair.At present, most automobile brake discs (drum) still adopt cast iron, and its major defect is that density is big, and this is unfavorable for alleviating car weight; The 2nd, poor thermal conductivity, its working-surface temperature is very high and thermograde is big, easily forms focus and produces ardent.So is is all researching and developing disc material countries in the world, as particle enhanced aluminum-based composite material so that the retarding disc for preparing not only loss of weight is energy-conservation, and can reduce vibration and noise in the brake process, shorten braking distance, improve braking effect.
CN1740354A discloses a kind of preparation method of in-situ grain reinforced high temperature aluminium base composite material, adopt the component and the weight percent of the in-situ grain reinforced high temperature aluminium base composite material that this method obtains to be: 11-13%Si, 0.5-1.5%Mg, 0.8-1.3%Cu, 0.8-1.5%Ni, 1-20%TiB
2, surplus is Al; This preparation method may further comprise the steps:
(1) add ZL 102 alloy and Al-Si master alloy or commercial-purity aluminium in crucible, heating up in the fusing back, covers with insulating covering agent, and insulating covering agent adopts the concise no sodium insulating covering agent of aluminium alloy;
(2) with KBF
4And KTiF
6Uniform mixing, the oven dry back adds in the melt, carries out mechanical stirring;
(3) after reaction finishes, take out by product, add technical pure Mg, Al-Ni and Al-Cu master alloy, take off removing dross, vacuumize and leave standstill;
(4) assembling median septum, riser pipe, mould, low pressure molding.
CN1492066A discloses a kind of automobile brake disc matrix material, it is characterized in that, this material is with generated in-situ Mg in casting solidification
2The disperse of Si enhanced granule is distributed in the alloy matrix aluminum that contains Si, Gu and forms, and its component weight percent content is: Mg
2Si15-35%, Si1-15%, Gu1-5%, Al surplus.
This automobile brake disc comprises following technological process with the preparation method of matrix material:
A) be that the Al-20%Si master alloy is a raw material with pure magnesium, fine copper, weight percent, batching back fusing as following weight percent: Gu1-5%, Mg9-23%, surplus are the Al-20% master alloy, and temperature of fusion is 680-900 ℃;
B) fusing back adds the insulating covering agent that to account for above-mentioned alloy total weight percent be 1-5%;
C) it is even to fusing and temperature at the 690-720 ℃ of adding pure magnesium that to account for above-mentioned alloy total weight percent be 9-23% to adjust temperature;
D) add the scouring agent that to account for above-mentioned alloy total weight percent be 1-2%, be incubated 5-10 minute;
E) add the alterant that to account for above-mentioned alloy total weight percent be 0.005-3%, insulation is more than 5 minutes;
F) press conventional cast technology casting.
Adopt the mechanical property of the goods that the bad matrix material that causes obtaining of the interfacial bonding property of wild phase particle and body material in the aluminum matrix composite that method for preparing obtains obtains behind die cast undesirable, the tensile strength and the Young's modulus of goods are relatively poor.
Embodiment
According to method provided by the invention, this method comprises the aluminium of molten state and KBF
4, K
2TiF
6Mix with the SiC particle; be cooled to 500-600 ℃ of reaction then; heat up again and make said mixture to molten state continue reaction; remove by product; obtain the aluminum matrix composite precursor; make described aluminum matrix composite precursor maintain molten state, and the aluminum matrix composite precursor of this molten state is mixed with magnesium, copper.
Intensification makes aluminium and KBF
4, K
2TiF
6Refer to aluminium, KBF with SiC particulate mixture to molten state
4, K
2TiF
6All be in molten state with the SiC particle.The temperature of described molten state is 1200-1800 ℃, is preferably 1200-1600 ℃.
Under the preferable case, with the aluminium and the KBF of molten state
4, K
2TiF
6Comprise with SiC particle blended method, under agitation, with KBF
4, K
2TiF
6Jet in molten state aluminium to powder and SiC uniform particles, by the shearing force that stirs with KBF
4, K
2TiF
6The aluminium thorough mixing of powder and SiC particle and molten state is even, to guarantee KBF
4, K
2TiF
6Can be evenly distributed in the aluminum matrix composite with the SiC particle.
In order to improve SiC particulate flowability, make SiC particle and aluminium base better mixing, under the preferable case, with the SiC particle with before the aluminium of molten state mixes, earlier with the preheating of SiC particle, the method of described preheating can adopt the method for this area routine, is 600-700 ℃ as the SiC particle being heated to temperature, and is incubated 1-2.5 hour.SiC particle after the preheating, the gas of its surface adsorption, moisture and impurity etc. have been removed, and surfactivity is improved, and therefore, flowability improves, and easier and aluminium molten state mix.
Described aluminium and KBF
4, K
2TiF
6With SiC particulate charge weight ratio be 1: 0.02-1.2: 0.02-1.2: 0.1-0.5 is preferably 1: 0.05-1: 0.05-1: 0.15-0.4.
According to method of the present invention, oxidized in order to prevent molten state aluminium, under the preferable case, described aluminium and KBF with molten state
4, K
2TiF
6Be blended in the rare gas element with the SiC particle and carry out; described rare gas element refers to not any one gas or the gaseous mixture with reactant and product generation chemical reaction; as in nitrogen, the periodic table of elements zero group gas one or more, be preferably in argon gas, nitrogen and the helium one or more.
For by the shearing force that stirs with KBF
4, K
2TiF
6With the aluminium thorough mixing of SiC particle and molten state, described stirring is preferably carried out under high-speed stirring, and stirring velocity is preferably 500-800 rev/min.
Described aluminium is 1 with the charge weight ratio of magnesium, copper: 0.01-0.08: 0.02-0.1.
In order further to improve the mechanical property of aluminum matrix composite, under the preferable case, this method comprises that also the aluminum matrix composite precursor with molten state mixes with silicon and/or nickel, described aluminum matrix composite precursor with molten state and silicon and/or nickel mix can with the aluminum matrix composite precursor of molten state and magnesium, copper blended simultaneously, before or after carry out, preferably simultaneously, the aluminum matrix composite precursor of molten state is mixed with silicon and/or nickel the aluminum matrix composite precursor of molten state and magnesium, copper blended.Described aluminium is 1 with the charge weight ratio of silicon, nickel: 0-0.2: 0-0.2.
According to the present invention, with the aluminium and the KBF of molten state
4, K
2TiF
6After mixing with the SiC particle, with aluminium and KBF
4, K
2TiF
6Reducing to 500-600 ℃ purpose with SiC particulate temperature of reaction is to make the aluminum matrix composite that obtains have good mechanical property.Because the semi-solid temperature of base aluminum is 565 ℃, at 550-570 ℃, reacts under the semi-solid temperature near base aluminum, can make the aluminum matrix composite that obtains have better mechanical property; Can also be the time by this material die cast, reduce conventional die casting inherent subsurface porosity and defective such as loose, improve casting quality, increase die life, therefore, preferably make described aluminium and KBF
4, K
2TiF
6Reduce to 550-570 ℃ of reaction with SiC particulate temperature of reaction.Described at 500-600 ℃, preferably the time of reacting under 550-570 ℃ can be for greater than 1 minute, reaction times surpasses after 60 minutes, the performance of the aluminum matrix composite that obtains has not had obvious variation, therefore at 500-600 ℃, the time of reacting under preferred 550-570 ℃ is preferably 5-60 minute.
Aluminium and KBF with molten state
4, K
2TiF
6After placing 500-600 ℃ of reaction to finish with SiC particulate mixture, it is in order to make reaction more thorough that this mixture is warming up to the purpose that molten state continues reaction.The time of reacting under the molten state of reaction mixture can be for greater than 1 minute, reaction times surpasses after 10 minutes, the performance of the aluminum matrix composite that obtains has not had obvious variation, and therefore the time of reacting under the molten state of mixture is preferably 5-10 minute.
In reaction process, the by product of generation comprises sylvite and the Al that generates in the reaction process
2O
3By products such as oxide inclusion, the method for removing described by product is conventionally known to one of skill in the art, in general, the method for removing described by product is included in the aluminum matrix composite precursor with before magnesium, copper mix, at aluminium and KBF
4, K
2TiF
6With adding scouring agent in the SiC particulate mixed melting thing and/or feeding rare gas element.
The kind of described scouring agent and add-on are conventionally known to one of skill in the art, as, described scouring agent can be selected from KCl, NaCl, NaSiF
6, Na
3AlF
6In one or more, the add-on of described scouring agent and aluminium, KBF
4, K
2TiF
6With the weight ratio of the total add-on of SiC particulate be 0.01-0.05: 1.
Add rare gas element and can make melts produce bubble, in floating-upward process, can adsorb Al by these bubbles
2O
3Inclusion makes it to float in the slag on mixture surface, has just removed by product when slag is salvaged out.In addition, the hydrogen that rare gas element can also absorption reaction generates in the process of come-up, and escape in the atmosphere, thereby reduced the concentration of hydrogen in the mixture.Described rare gas element can feed in the mixture by conduit, as graphite guide tube.The kind of described rare gas element and add-on are conventionally known to one of skill in the art, be selected from and both be insoluble to melts, again not with the gas of melts and hydrogen reaction, as in nitrogen, the periodic table of elements zero group gas one or more.
With the method for aluminum matrix composite die cast is conventionally known to one of skill in the art, as, described forming method can adopt low pressure molding or high-pressure molding, and the present invention preferably adopts the method for high-pressure molding that aluminum matrix composite is carried out die cast.The method of described high-pressure molding comprises transfer mold is preheated to 200-300 ℃, aluminum matrix composite with molten state pours in the chamber of transfer mold then, type is filled in the die casting of pressurizeing to aluminum matrix composite, described mold filling pressure is the 60-110 MPa, keep top pressure 5-15 second, finish this die casting operation after the goods that obtain are solidified fully, obtain the goods that obtain by after the described aluminum matrix composite compression moulding.
Below will the present invention will be further described by specific embodiment.
Embodiment 1
Present embodiment illustrates the preparation method of aluminum matrix composite provided by the invention and goods.
Under 720 ℃, in resistance furnace, add 80 gram commercial-purity aluminiums, make the aluminium fusion, then, under nitrogen protection, and under 650 rev/mins stirring velocity, with 4 gram KBF
4Powder, 4 gram K
2TiF
6(Weifang Bond's special material company limited buys through the alpha-silicon carbide particle of 650 ℃ of preheatings for powder and 30 grams; particle diameter 1000 nanometers) jet equably in molten aluminum; with fused aluminium thorough mixing; then, be cooled to 565 ℃, under nitrogen protection; and after reacting 30 minutes under 650 rev/mins the stirring velocity, stop to stir; heat up again said mixture to molten state (1200 ℃), reacted 8 minutes, add 2 gram scouring agent NaSiF then
6And stir and to obtain the aluminum matrix composite precursor after removing by product, this aluminum matrix composite precursor is continued to maintain molten state (1200 ℃), and adding 1.2 gram technical pure Mg, 2.4 restrain Cu in the aluminum matrix composite precursor of this molten state, mix, remove removing dross, obtain aluminum matrix composite.
Retarding disc metal mold transfer mold is preheating to 200 ℃, set die-casting technological parameter, described processing parameter comprises that two positions are made as 280 ± 30 millimeters, a position is made as 130 ± 30 millimeters, the die sinking time is 4.5 ± 2 seconds, ejecting time-delay is 4.0 ± 2 seconds, pumping rate is 4.0 ± 2 circles, close die cavity then, pour into the above-mentioned aluminum matrix composite melt that obtains, type is filled in pressurization die casting, reach the top pressure of 110 MPas until squeeze pressure, keep maximal pressure casting pressure 5 seconds, and treated that composite castings solidified fully, obtain retarding disc A1 provided by the invention.Behind the die cast, A1 carries out T6 thermal treatment to these goods.
Embodiment 2
Present embodiment illustrates the preparation method of aluminum matrix composite provided by the invention and goods.
Under 720 ℃, in resistance furnace, add 80 gram commercial-purity aluminiums, make the aluminium fusion, then, under argon shield, and under 600 rev/mins stirring velocity, with 14 gram KBF
4Powder, 12 gram K
2TiF
6(Weifang Bond's special material company limited buys through the alpha-silicon carbide particle of 650 ℃ of preheatings for powder and 24 grams; particle diameter 1000 nanometers) jet equably in molten aluminum; with fused aluminium thorough mixing; then; be cooled to 560 ℃; under nitrogen protection; and after reacting 30 minutes under 600 rev/mins the stirring velocity, stop to stir; heat up again said mixture to molten state (1300 ℃); reacted 5 minutes; add 2 gram scouring agent NaCl then, and stir and obtain the aluminum matrix composite precursor after removing by product, this aluminum matrix composite precursor is continued to maintain molten state (1300 ℃); and adding 1.6 restrains Mg in the aluminum matrix composite precursor of this molten state; 3.2 gram Cu; 1.2 gram silicon and 0.6 gram nickel; mix, remove removing dross, obtain aluminum matrix composite.
Retarding disc metal mold transfer mold is preheating to 250 ℃, set die-casting technological parameter, described processing parameter comprises that two positions are made as 280 ± 30 millimeters, a position is made as 130 ± 30 millimeters, the die sinking time is 4.5 ± 2 seconds, ejecting time-delay is 4.0 ± 2 seconds, pumping rate is 4.0 ± 2 circles, close die cavity then, pour into the above-mentioned aluminum matrix composite melt that obtains, type is filled in pressurization die casting, reach the top pressure of 110 MPas until squeeze pressure, keep maximal pressure casting pressure 10 seconds, and treated that composite castings solidified fully, obtain retarding disc A2 provided by the invention.Behind the die cast, A2 carries out T6 thermal treatment to these goods.
Embodiment 3
Present embodiment illustrates the preparation method of aluminum matrix composite provided by the invention and goods.
Under 720 ℃, in resistance furnace, add 80 gram commercial-purity aluminiums, make the aluminium fusion, then, under argon shield, and under 650 rev/mins stirring velocity, with 30 gram KBF
4Powder, 35 gram K
2TiF
6(Weifang Bond's special material company limited buys through the alpha-silicon carbide particle of 650 ℃ of preheatings for powder and 16 grams; particle diameter 1000 nanometers) jet equably in molten aluminum; with fused aluminium thorough mixing; then, be cooled to 565 ℃, under nitrogen protection; and after reacting 50 minutes under 650 rev/mins the stirring velocity, stop to stir; heat up again said mixture to molten state (1400 ℃), reacted 10 minutes, add 2 gram scouring agent NaCl and 2 gram scouring agent Na then
3AlF
6And stir and to obtain the aluminum matrix composite precursor after removing by product, this aluminum matrix composite precursor is continued to maintain molten state (1400 ℃), and adding 3.2 gram Mg, 4 gram Cu and 9 restrain silicon in the aluminum matrix composite precursor of this molten state, mix, remove removing dross, obtain aluminum matrix composite.
Retarding disc metal mold transfer mold is preheating to 200 ℃, set die-casting technological parameter, described processing parameter comprises that two positions are made as 280 ± 30 millimeters, a position is made as 130 ± 30 millimeters, the die sinking time is 4.5 ± 2 seconds, ejecting time-delay is 4.0 ± 2 seconds, pumping rate is 4.0 ± 2 circles, close die cavity then, pour into the above-mentioned aluminum matrix composite melt that obtains, type is filled in pressurization die casting, reach the top pressure of 110 MPas until squeeze pressure, keep maximal pressure casting pressure 15 seconds, and treated that composite castings solidified fully, obtain retarding disc A3 provided by the invention.Behind the die cast, A3 carries out T6 thermal treatment to these goods.
Embodiment 4
Present embodiment illustrates the preparation method of aluminum matrix composite provided by the invention and goods.
Under 720 ℃, in resistance furnace, add 80 gram commercial-purity aluminiums, make the aluminium fusion, then, under the helium protection, and under 650 rev/mins stirring velocity, with 60 gram KBF
4Powder, 56 gram K
2TiF
6(Weifang Bond's special material company limited buys through the alpha-silicon carbide particle of 650 ℃ of preheatings for powder and 12 grams; particle diameter 1000 nanometers) jet equably in molten aluminum; with fused aluminium thorough mixing; then, be cooled to 565 ℃, under the helium protection; and after reacting 25 minutes under 650 rev/mins the stirring velocity, stop to stir; heat up again said mixture to molten state (1550 ℃), reacted 10 minutes, add 3 gram scouring agent NaCl and 3 gram scouring agent Na then
3AlF
6In molten mixture, feed simultaneously and obtain the aluminum matrix composite precursor after by product is removed in nitrogen and stirring, this aluminum matrix composite precursor is continued to maintain molten state (1550 ℃), and adding 4 gram Mg, 5.6 gram Cu and 1 restrain nickel in the aluminum matrix composite precursor of this molten state, mix, remove removing dross, obtain aluminum matrix composite.
Retarding disc metal mold transfer mold is preheating to 240 ℃, set die-casting technological parameter, described processing parameter comprises that two positions are made as 280 ± 30 millimeters, a position is made as 130 ± 30 millimeters, the die sinking time is 4.5 ± 2 seconds, ejecting time-delay is 4.0 ± 2 seconds, pumping rate is 4.0 ± 2 circles, close die cavity then, pour into the above-mentioned aluminum matrix composite melt that obtains, type is filled in pressurization die casting, reach the top pressure of 110 MPas until squeeze pressure, keep maximal pressure casting pressure 15 seconds, and treated that composite castings solidified fully, obtain retarding disc A4 provided by the invention.Behind the die cast, A4 carries out T6 thermal treatment to these goods.
Embodiment 5
Present embodiment illustrates the preparation method of aluminum matrix composite provided by the invention and goods.
Under 720 ℃, in resistance furnace, add 80 gram commercial-purity aluminiums, make the aluminium fusion, then, under argon shield, and under 650 rev/mins stirring velocity, with 65 gram KBF
4Powder, 60 gram K
2TiF
6(Weifang Bond's special material company limited buys through the alpha-silicon carbide particle of 650 ℃ of preheatings for powder and 15 grams; particle diameter 1000 nanometers) jet equably in molten aluminum; with fused aluminium thorough mixing; then, be cooled to 565 ℃, under argon shield; and after reacting 25 minutes under 650 rev/mins the stirring velocity, stop to stir; heat up again said mixture to molten state (1580 ℃), reacted 10 minutes, add 4 gram scouring agent Na then
3AlF
6In molten mixture, feed simultaneously and obtain the aluminum matrix composite precursor after by product is removed in nitrogen and stirring, this aluminum matrix composite precursor is continued to maintain molten state (1580 ℃), and adding 4.8 gram Mg, 7 gram Cu, 3 gram silicon and 1.2 restrain nickel in the aluminum matrix composite precursor of this molten state, mix, remove removing dross, obtain aluminum matrix composite.
Retarding disc metal mold transfer mold is preheating to 240 ℃, set die-casting technological parameter, described processing parameter comprises that two positions are made as 280 ± 30 millimeters, a position is made as 130 ± 30 millimeters, the die sinking time is 4.5 ± 2 seconds, ejecting time-delay is 4.0 ± 2 seconds, pumping rate is 4.0 ± 2 circles, close die cavity then, pour into the above-mentioned aluminum matrix composite melt that obtains, type is filled in pressurization die casting, reach the top pressure of 110 MPas until squeeze pressure, keep maximal pressure casting pressure 15 seconds, and treated that composite castings solidified fully, obtain retarding disc A5 provided by the invention.Behind the die cast, A5 carries out T6 thermal treatment to these goods.
Comparative Examples 1
The aluminum matrix composite that this Comparative Examples explanation prior art provides and the preparation method of goods.
Prepare aluminum matrix composite according to CN1740354A embodiment 1 disclosed method, and, obtain reference goods retarding disc B1 according to the above-mentioned aluminum matrix composite of die casting parameter die casting in the embodiment of the invention 1 method.Behind the die cast, goods B1 is carried out T6 thermal treatment.
Embodiment 6-10
This group embodiment illustrates the performance of goods provided by the invention.
Goods A1-A5 to embodiment 1-5 preparation carries out every performance test, and testing method is as follows:
(new three thinks measurement technology company limited, CMT5205) goes up tensile strength, yield strength, elongation at break, Young's modulus and the Brinell hardness of measuring goods, and test result is shown in following table 1 in the universal material experimental machine with GB GBT 228 standards.
Comparative Examples 2
The performance of the goods that this Comparative Examples explanation prior art provides.
Goods B1 to Comparative Examples 1 preparation carries out every performance test, and testing method is as follows:
(new three thinks measurement technology company limited, CMT5205) goes up tensile strength, yield strength, elongation at break, Young's modulus and the Brinell hardness of measuring goods, and test result is shown in following table 1 in the universal material experimental machine with GB GBT 228 standards.
Table 1
The embodiment numbering |
The goods numbering |
Tensile strength (MPa) |
Yield strength (MPa) |
Elongation at break (%) |
Young's modulus (gpa) |
Brinell hardness (HB) |
Embodiment 6 |
A1 |
482 |
321 |
5.0 |
101 |
147 |
Embodiment 7 |
A2 |
519 |
401 |
5.9 |
113 |
169 |
Embodiment 8 |
A3 |
490 |
345 |
5.6 |
104 |
171 |
Embodiment 9 |
A4 |
501 |
353 |
5.7 |
109 |
172 |
Embodiment 10 |
A5 |
523 |
405 |
6.1 |
114 |
173 |
Comparative Examples 2 |
B1 |
352 |
303 |
3.3 |
82 |
118 |
By last table 1 as can be seen, the goods B1 that obtains with respect to the aluminum matrix composite die cast of prior art, the tensile strength of the goods A1-A5 that aluminum matrix composite die cast of the present invention obtains has improved 36.9-48.6%, yield strength has improved 5.9-33.6%, elongation at break has increased 51.5-84.8%, Young's modulus has improved 23.2-39%, Brinell hardness has improved 24.6-46.6%, the good mechanical properties of the goods that the aluminum matrix composite die cast that as seen adopts method provided by the invention to obtain obtains and being significantly improved.