A kind of preparation method of dispersion-strengthened aluminum matrix composite
Technical field
The invention belongs to the aluminum matrix composite preparing technical field, a kind of preparation method of nano particle dispersion-strengthened aluminum matrix composite particularly is provided.
Technical background
Excellent physicals and the mechanical properties such as that aluminum matrix composite has is lightweight, specific tenacity is high, specific modulus is high, thermal expansivity is low, high temperature resistant, wear-resistant, dimensional stabilizing are widely used in the fields such as aerospace, military and national defense and communications and transportation, Electronic Packaging.Wherein, the dispersion-strengthened aluminum matrix composite has the characteristics such as cost is low, preparation technology simple, performance is more outstanding, becomes gradually the study hotspot in domestic and international aluminum matrix composite field.Dispersion-strengthened aluminum matrix composite technology of preparing commonly used has powder metallurgic method and two kinds of techniques of casting.The complex process equipment of powder metallurgic method, high expensive are difficult for preparation large volume and complex-shaped part, and have in process of production the danger such as dust-firing and blast.And casting technique is simple, and is easy to operate, can prepare the matrix material of large volume, and equipment investment is few, and production cost is low, and productivity is high, the suitability for industrialized scale production.
Traditional aluminum matrix composite is that enhanced granule is applied in aluminum substrate, to exist between enhanced granule and matrix wettability poor owing to adding particle in aluminum substrate, surface reaction is difficult to control, and the defectives such as enhanced granule skewness have affected the performance of aluminum matrix composite.How to improve the wettability between enhanced granule and matrix, improve the interface performance of material, become when previous problem demanding prompt solution.
The high-energy ultrasonic method be a kind of with nanoparticulate dispersed the effective ways in the aluminium alloy melt.The high-energy ultrasonic ratio juris is to utilize sound cavitation effect that ultrasonic wave produces in aluminium alloy melt and the stirring in the caused mechanics effect of acoustic streaming effect, dispersion, degasification etc. to be used for promoting nano particle to sneak into aluminium alloy melt; improve the wettability between nano particle and aluminium alloy melt, force nano particle Uniform Dispersion in aluminium alloy melt.The high-energy ultrasonic method is the preparation method of a kind of simple process, dispersion-strengthened aluminum matrix composite with low cost.But, according to conventional cast technique, single enhanced granule being applied in aluminium alloy melt, most of enhanced granule can float over bath surface or adhere to the smelting pot inwall in the high-energy ultrasonic dispersion process, is difficult for Uniform Dispersion and enters in whole aluminium alloy melt.Therefore, disperse inhomogeneously in the final aluminum matrix composite that obtains on the enhanced granule macroscopic view, consistency of performance is poor.
Summary of the invention
The object of the invention is to overcome disperse on the enhanced granule macroscopic view in the aluminum matrix composite that prior art exists inhomogeneous, the problem that consistency of performance is poor, a kind of preparation method of dispersion-strengthened aluminum matrix composite is provided, the dispersion-strengthened aluminum matrix composite exists fragility phase and the inhomogeneous defective of distribution of material, nano level Al to make it solve in the past
2O
3Particle evenly distributes in matrix, has played dispersion-strengthened action, and the strength and modulus of matrix is improved significantly.
At first a kind of preparation method of dispersion-strengthened aluminum matrix composite adopts sol-gel method to prepare CuO/Al
2O
3Nano composite powder makes nanometer Al
2O
3Mix with the CuO uniform particles, to guarantee nanometer Al
2O
3The follow-up abundant dispersion of particle enters aluminium alloy melt inside, then adopts the standby dispersion-strengthened aluminum matrix composite of high-energy ultrasonic legal system.Concrete grammar comprises following content:
1, sol-gel method prepares CuO/Al
2O
3Nano composite powder
(1) with soluble copper salt and exsiccated ammonium alum (NH
4Al (SO
4)
2) be raw material, be mixed with the aqueous solution of 0.1~25 mol/L as reaction mother liquor, prepare certain density bicarbonate of ammonia (NH
4HCO
3) solution is as precipitation agent, according to CuO/Al
2O
3Middle Al
2O
3Content is determined mantoquita and exsiccated ammonium alum (NH
4Al (SO
4)
2) amount, according to NH
4Al (SO
4)
2With NH
4HCO
3Mol ratio be 1:4 and Cu
2+With NH
4HCO
3Mol ratio be that 1:2 determines NH
4HCO
3Amount.
(2) precipitant solution is added in reaction mother liquor, add 0.5~1.0 mol/L NH simultaneously in reaction system
3H
2It is neutral that O regulation system pH value remains, after continuing to stir 10~60 min, ultra-sonic dispersion 5~30 min obtain the water-sol, and stirring velocity is 100~500 r/min, and ultrasonic power is 100~1000 W.
(3) with after above-mentioned gained water-sol ageing 10~24 h, remove supernatant liquid, get gel after centrifuge dehydration.Pulverize after under 80 ℃, gel being dried, calcine 60~120 min and namely get CuO/Al in 500~800 ℃ of air
2O
3Nano composite powder.
2, the standby dispersion-strengthened aluminum matrix composite of high-energy ultrasonic legal system
(1) the technical pure aluminum or aluminum alloy is placed in crucible electrical resistance furnace, is warming up to higher than 50~80 ℃ of technical pure aluminum or aluminum alloy fusing points and makes its fusing, after processing through the degasification slagging-off, obtain clean fine aluminium or aluminium alloy melt.
(2) continue to be warming up to 750~850 ℃, with the CuO/Al of aluminium foil parcel
2O
3Nano composite powder pushes melt inside with the graphite sleeve, turn on agitator simultaneously, and stirring velocity is 500~1000 r/min, churning time is 10~30 min, obtains compounding flux.
(4) high-energy ultrasonic is processed compounding flux, and frequency is 17~20 KHz, and peak power output is 1~2 KW, and the treatment time is 5~30 min.
(5) above-mentioned compounding flux is cooled to 680~720 ℃, is poured in the metal type dies of 250~300 ℃ of preheatings, the cooling rear demoulding namely gets the dispersion-strengthened aluminum matrix composite.
Step a(1) CuO/Al described in
2O
3Al in nano composite powder
2O
3Content is 10wt.%~90 wt.%.
Step a(1) soluble copper salt described in comprises any one or a few in copper sulfate, cupric chloride, cupric nitrate.
Step b(1) aluminium alloy described in can be any one or a few during Al-Si, Al-Cu, Al-Mg, Al-Zn are.
Step b(2) CuO/Al described in
2O
3The add-on of nano composite powder is the 0.2wt.%~2.0 wt.% of dispersion-strengthened aluminum matrix composite.
Step b(2) CuO/Al described in
2O
3Nano composite powder add mode for add in batches, be divided into 2~5 equal portions.
Compared with prior art, superiority of the present invention is:
(1) adopt sol-gel method to prepare CuO/Al
2O
3Nano composite powder makes nanometer Al
2O
3Mix with the CuO uniform particles, guarantee on the one hand nanometer Al
2O
3The follow-up abundant dispersion of particle enters aluminium alloy melt inside, on the other hand when nanometer CuO and molten aluminium generation thermite reaction, due to Al
2O
3The existence of particle is played certain " solid diluting effect " to nanometer CuO powder, prevents that reaction process from blasting, and the Cu that thermite reaction generates plays solution strengthening effect, has improved simultaneously Al
2O
3The interface wet ability of particle and aluminum substrate, thus the interface performance of matrix material improved.
(2) utilize the graphite sleeve with CuO/Al
2O
3Nano composite powder pushes melt inside, has solved the problem that enhanced granule that traditional enhanced granule mode that adds produces floats over bath surface or adheres to the smelting pot inwall.
(3) under the high-energy ultrasonic effect, the rolling disturbance that utilizes simultaneously violent surface reaction to form realizes the nanometer Al that surface reaction generates
2O
3Particle and CuO/Al
2O
3The nanometer Al that nano composite powder is directly introduced
2O
3The disperse of particle in whole aluminium alloy melt distributes, and strengthening effect further strengthens.
(4) adopt the aluminum matrix composite of the inventive method preparation, have the performance of high abrasion, high tenacity, have a extensive future.
Embodiment
Embodiment 1
(1) sol-gel method prepares CuO/Al
2O
3Nano composite powder: preparation 0.1 mol/L CuSO
4, 1.4 mol/L NH
4Al (SO
4)
2) the aqueous solution as reaction mother liquor, the preparation 5.8 mol/L NH
4HCO
3Solution adds 500 ml precipitant solution in 500 ml reaction mother liquors as precipitation agent, adds 0.5 mol/L NH simultaneously in reaction system
3H
2It is neutral that O regulation system pH value remains, with ultra-sonic dispersion 5 min after the lasting stirring of 100 r/min stirring velocitys 10 min, ultrasonic power is 100 W.After above-mentioned gained water-sol ageing 10 h, remove supernatant liquid, get gel after centrifuge dehydration.Pulverize after under 80 ℃, gel being dried, calcining 60 min namely get CuO/Al in 500 ℃ of air
2O
3Nano composite powder, wherein Al
2O
3Content is 90wt.%.
(2) the standby dispersion-strengthened aluminum matrix composite of high-energy ultrasonic legal system: 500 g commercial-purity aluminiums are placed in crucible electrical resistance furnace, are warming up to 710 ℃ and make its fusing, after processing through the degasification slagging-off, obtain clean melt.Continue to be warming up to 750 ℃, with 10 g CuO/Al
2O
3Nano composite powder is divided equally 5 parts, pushes molten aluminium inside with the graphite sleeve after aluminium foil parcel, stirs 10 min with 1000 r/min stirring velocitys, acquisition clad aluminum melt.Afterwards the clad aluminum melt is applied supersound process 30 min of frequency 20 KHz, peak power output 1 KW.Above-mentioned melt is cooled to 680 ℃, is poured in the metal type dies of 250 ℃ of preheatings, the cooling rear demoulding namely gets the dispersion-strengthened aluminum matrix composite.
Embodiment 2
(1) sol-gel method prepares CuO/Al
2O
3Nano composite powder: preparation 5.8 mol/L Cu (NO
3)
2, 10 mol/L NH
4Al (SO
4)
2) the aqueous solution as reaction mother liquor, the preparation 51.6 mol/L NH
4HCO
3Solution adds 500 ml precipitant solution in 500 ml reaction mother liquors as precipitation agent, adds 1.0 mol/L NH simultaneously in reaction system
3H
2It is neutral that O regulation system pH value remains, with ultra-sonic dispersion 30 min after the lasting stirring of 500 r/min stirring velocitys 60 min, ultrasonic power is 1000 W.After above-mentioned gained water-sol ageing 24 h, remove supernatant liquid, get gel after centrifuge dehydration.Pulverize after under 80 ℃, gel being dried, calcining 120 min namely get CuO/Al in 900 ℃ of air
2O
3Nano composite powder, wherein Al
2O
3Content is 10wt.%.
(2) the standby dispersion-strengthened aluminum matrix composite of high-energy ultrasonic legal system: 800 g 2024 aluminium alloys are placed in crucible electrical resistance furnace, are warming up to 750 ℃ and make its fusing, after processing through the degasification slagging-off, obtain clean melt.Continue to be warming up to 850 ℃, with 1.6 g CuO/Al
2O
3Nano composite powder is divided equally 2 parts, pushes molten aluminium inside with the graphite sleeve after aluminium foil parcel, stirs 30 min with 500 r/min stirring velocitys, acquisition clad aluminum melt.Afterwards the clad aluminum melt is applied supersound process 5 min of frequency 17 KHz, peak power output 2 KW.Above-mentioned melt is cooled to 700 ℃, is poured in the metal type dies of 300 ℃ of preheatings, the cooling rear demoulding namely gets the dispersion-strengthened aluminum matrix composite.
Embodiment 3
(1) sol-gel method prepares CuO/Al
2O
3Nano composite powder: preparation 3.2 mol/L CuCl
2, 5 mol/L NH
4Al (SO
4)
2) the aqueous solution as reaction mother liquor, the preparation 26.4 mol/L NH
4HCO
3Solution adds 500 ml precipitant solution in 500 ml reaction mother liquors as precipitation agent, adds 0.8 mol/L NH simultaneously in reaction system
3H
2It is neutral that O regulation system pH value remains, with ultra-sonic dispersion 20 min after the lasting stirring of 300 r/min stirring velocitys 30 min, ultrasonic power is 600 W.After above-mentioned gained water-sol ageing 18 h, remove supernatant liquid, get gel after centrifuge dehydration.Pulverize after under 80 ℃, gel being dried, calcining 90 min namely get CuO/Al in 750 ℃ of air
2O
3Nano composite powder, wherein Al
2O
3Content is 50wt.%.
(2) the standby dispersion-strengthened aluminum matrix composite of high-energy ultrasonic legal system: 400 g 6063 aluminium alloys are placed in crucible electrical resistance furnace, are warming up to 730 ℃ and make its fusing, after processing through the degasification slagging-off, obtain clean melt.Continue to be warming up to 800 ℃, with 4 g CuO/Al
2O
3Nano composite powder is divided equally 4 parts, pushes molten aluminium inside with the graphite sleeve after aluminium foil parcel, stirs 20 min with 800 r/min stirring velocitys, acquisition clad aluminum melt.Afterwards the clad aluminum melt is applied supersound process 15 min of frequency 19 KHz, peak power output 1.5 KW.Above-mentioned melt is cooled to 720 ℃, is poured in the metal type dies of 300 ℃ of preheatings, the cooling rear demoulding namely gets the dispersion-strengthened aluminum matrix composite.