Patent Publication Number: US-10309000-B2

Title: Method for preparing aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The application claims priority to Chinese Application No. 201510296735.8, filed on Jun. 2, 2015, the contents of which are hereby incorporated herein by reference. 
     BACKGROUND 
     Field of Invention 
     The present invention relates to a method for preparing an aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite, which belongs to a technical field of preparation and use of non-ferrous metal materials. 
     Background of the Invention 
     Since aluminum alloys being a non-ferrous metal alloy have good intensity, toughness and electrically and thermally conductive performances, they are usually used as structural materials and are widely used in the fields of aerospace, electronic industry, and automobile manufacturing. However, aluminum alloys have low hardness, low tensile strength and poor corrosion resistance, so that there is a large limit to aluminum alloys in industrial application. 
     Since quasicrystal materials have the disadvantages of brittleness and loose microstructure, it is very difficult to use quasicrystal materials as structural materials. However, quasicrystals have overall performances of high hardness, non-stickiness, low expansivity, wear-resistance, heat resistance, corrosion resistance and low friction coefficient, so that they can be used as a reinforcement phase in composites to improve mechanical properties of the composites. 
     Since silicon carbide has the advantages of low price, high wear-resistance and direct casting forming and has low manufacturing cost, it can be used as structural parts and wear-resistant parts in the automobile, aerospace and military industries. 
     Currently, it is in research phase that aluminum matrix composites are prepared using the mixture of aluminum-copper-iron quasicrystal and silicon carbide as a reinforcement phase, therefore, preparing technology also need to be improved. 
     SUMMARY 
     Invention Object 
     For the case of background art, the object of the present invention is to provide a method for preparing an aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite with an aluminum alloy as a matrix and with aluminum-copper-iron quasicrystal and silicon carbide as reinforcement agents via smelting in a vacuum melting furnace, casting and heat treatment, thereby improving mechanical properties of the aluminum matrix composite and extending its application range. 
     Technical Solution 
     Chemical materials used in the invention are aluminum alloy, aluminum-copper-iron quasicrystal, silicon carbide, zinc oxide, waterglass, aluminum foil, graphite, acetone, deionized water and argon; with gram (g), milliliter (mL) and cubic centimeter (cm 3 ) as unit of measurement, the chemical materials have the following usage amount: 
     3800 g±1 g of aluminum alloy which is ZAlSi 7 Mg and a solid bulk, 50 g±1 g of aluminum-copper-iron quasicrystal which is Al 63 Cu 25 Fe 12  and solid particles, 50 g±1 g of silicon carbide which is SiC and solid particles, 100 g±1 g of zinc oxide which is ZnO and solid powders, 25 g±1 g of waterglass which is Na 2 SiO 3 .9H 2 O and solid powders, aluminum foil with the size of 2000 mm×0.5 mm×2000 mm which is Al and a paper-like solid, graphite with the size of Φ200 mm×400 mm which is C and a solid bulk, 800 mL±10 mL of acetone which is C 3 H 6 O and liquid, 1000 mL±50 mL of deionized water which is H 2 O and liquid, and 100000 cm 3 ±100 cm 3  of argon which is Ar and gas. 
     The method has the following steps of: 
     (1) preparing a casting mould, consisting of: 
     making a cylindrical casting mould of which the cavity has the size of Φ100 mm×200 mm and has surface roughness of Ra0.08-0.16 μm, using graphite materials; 
     (2) preparing a coating agent, consisting of: 
     weighing out 100 g±1 g of zinc oxide and 25 g±1 g of waterglass, and measuring out 600 mL±5 mL of deionized water; and adding 100 g±1 g of zinc oxide, 25 g±1 g of waterglass and 600 mL±5 mL of deionized water into a slurry mixer and stirring at 50 r/min for 100 min; 
     obtaining milk-white suspending liquid being called as the coating agent after stirring; 
     (3) pretreating aluminum-copper-iron quasicrystal and silicon carbide, consisting of: 
     {circle around (1)} ball-milling, including: weighing out 50 g±1 g of aluminum-copper-iron quasicrystal and 50 g+1 g of silicon carbide, placing 50 g±1 g of aluminum-copper-iron quasicrystal and 50 g±1 g of silicon carbide into a jar of a ball mill, and mixing and ball-milling for 5 hours, thereby obtaining mixed fine powders after ball-milling; 
     {circle around (2)} dispersing and washing by ultrasonic wave, including: placing the mixed fine powders obtained after ball-milling into a beaker, adding 400 mL of acetone and then mixing; and 
     placing the beaker in an ultrasonic dispersion instrument, and dispersing and washing by ultrasonic wave for 100 min at the frequency of 28 kHz, thereby obtaining a mixed liquid; 
     {circle around (3)} filtrating, including: placing the mixed liquid into a Buchner funnel of a suction flask, filtrating using a millipore membrane, keeping a filter cake and removing washing liquid; and 
     {circle around (4)} vacuum drying, including: placing the filter cake into a quartz container, and then placing the quartz container in a vacuum drying oven and drying at the temperature of 200□ for 60 min under the vacuum degree of 8 Pa, thereby obtaining aluminum-copper-iron quasicrystal and silicon carbide mixed fine powders after drying; 
     (4) pretreating aluminum alloy, consisting of: 
     {circle around (1)} cutting the aluminum alloy bulk into small pieces of which the size is less than 50 mm×50 mm×50 mm using a machine, 
     {circle around (2)} coating the aluminum alloy pieces obtained after cutting using aluminum foils, and 
     {circle around (3)} preheating, including: placing the coated aluminum alloy pieces into a heating furnace and preheating at the temperature of 200□ for 60 min; 
     (5) smelting to obtain the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite, which is performed in a intermediate-frequency induction melting furnace through the process of intermediate-frequency induction heating, vacuumizing, bottom blowing argon, and casting molding, consisting of: 
     {circle around (1)} pretreating the cylindrical graphite mould, including: 
     washing the cavity of the cylindrical graphite mould using acetone to be clean, 
     uniformly applying the prepared coating agent to the surface of the cavity of the cylindrical graphite mould, and making the coating layer have the thickness of 1 mm, and 
     placing the cylindrical graphite mould in a drying oven and preheating at the temperature of 200□; 
     {circle around (2)} opening the intermediate-frequency induction melting furnace, cleaning an inside of a graphite melting crucible, and washing using acetone to clean the inside of the crucible; 
     {circle around (3)} placing 3800 g±1 g of the aluminum alloy pieces coated by the aluminum foils at the bottom of the crucible, and placing 50 g±1 g of aluminum-copper-iron quasicrystal and 50 g±1 g of silicon carbide on the aluminum alloy pieces; 
     {circle around (4)} closing and sealing the intermediate-frequency induction melting furnace, including: 
     opening a vacuum pump, removing the air from the furnace to make pressure in the furnace be less than 10 Pa, and 
     opening a heater of the intermediate-frequency induction melting furnace and heating at the temperature of 600□±5□; 
     {circle around (5)} passing a bottom blowing argon tube through the bottom of the graphite crucible, transmitting argon to the inside of the crucible at the speed of 1000 C 3 /min, so as to keep the pressure in the furnace to be 0.045 Mpa, and controlling the pressure in the furnace by a gas outlet tube valve; and 
     continuously heating, and smelting at the temperature of 720□±5□ and keeping the constant temperature of 720□±5□ for 20 min; 
     {circle around (6)} casting, including: 
     closing the bottom blowing argon tube and removing slag on the surface of melt in the crucible, and 
     aligning a gate of the preheated cylindrical mould, and casting until filled; 
     {circle around (7)} cooling the mould with alloy melt to 25□ in the air; and 
     {circle around (8)} opening the mould after cooling, thereby obtaining the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite; 
     (6) heat-treating casting, consisting of: 
     placing the casting in a vacuum heat treatment furnace, and heat-treating at the temperature of 535□±5□ under vacuum degree of 8 Pa for 8 h to complete solid solution; 
     (7) quickly placing the casting in a mesothermal cooling water tank after heat-treating and quenching using water with 65□ for 45 s; 
     (8) placing the casting in a heat treatment furnace after quenching and performing aging-treatment at the temperature of 180□±5□ for 6 h; 
     (9) washing the surface of the casting with acetone to make each surface be clean; and 
     (10) detecting, analyzing and representing color, microstructure and mechanical property of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite, consisting of: 
     performing XRD analysis by X-ray diffractometer; 
     performing analysis of tensile strength by a microcomputer control electron universal testing machine; 
     performing hardness analysis by a Brinell Hardness tester; and 
     making a conclusion which is that the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite is bulk, hardness of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite reaches 80.3 HB and is improved by 50.64%, tensile strength of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite reaches 285 Mpa and is improved by 60.42%, and corrosion resistance of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite is improved by 40%. 
     Beneficial Effects 
     In comparison with background art, the present invention has obvious advancement. For the case of low hardness and low tensile strength of aluminum matrix composites, in the present application, an aluminum matrix composite reinforced with the mixture of aluminum-copper-iron quasicrystal and silicon carbide is prepared with an aluminum alloy as a matrix and with aluminum-copper-iron quasicrystal and silicon carbide as reinforcement agents via smelting in a vacuum melting furnace, protection of bottom blowing argon, casting and vacuum heat-treatment. The preparing method has advanced technology, strict process, and accurate and detailed data. The prepared aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite has hardness of 80.3 HB which is improved by 50.64% and tensile strength of 285 Mpa which is improved by 60.42%, and corrosion resistance thereof is improved by 40%. The method is a perfect method for preparing an aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view in smelting state of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite; 
         FIG. 2  is a diffraction intensity pattern of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite; 
         FIG. 3  is a metallographic structure micrograph of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite; 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     As shown in the Figures, the list of reference numerals is as follows: 
     the intermediate-frequency induction smelting furnace is represented by  1 ; the furnace base is represented by  2 ; the furnace chamber is represented by  3 ; the gas outlet tube is represented by  4 ; the gas outlet valve is represented by  5 ; the working table is represented by  6 ; the graphite melting crucible is represented by  7 ; the intermediate-frequency induction heater is represented by  8 ; the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite melt is represented by  9 ; argon is represented by  10 ; the bottom blowing motor is represented by  11 ; the bottom blowing tube is represented by  12 ; the vacuum pump is represented by  13 ; the vacuum tube is represented by  14 ; the argon tank is represented by  15 ; the argon tube is represented by  16 ; the argon valve is represented by  17 ; the electric cabinet is represented by  18 ; the display screen is represented by  19 ; the indicator light is represented by  20 ; the power switch is represented by  21 ; the intermediate-frequency heat controller is represented by  22 ; the bottom blowing motor controller is represented by  23 ; the vacuum pump controller is represented by  24 ; the first cable is represented by  25 ; the second cable is represented by  26 . 
     In combination with the drawings, the present application is further described in detail below. 
     A view in smelting state of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite is shown in  FIG. 1 , each part need be correct in position, ratio is conducted according to amount, and operation is conducted according to order. 
     Usage amount of each of the chemical materials in preparation is determined on the basis of the range set in advance, with gram, milliliter and cubic centimeter as unit of measurement. 
     Smelting to obtain the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite is performed in an intermediate-frequency induction melting furnace through the process of intermediate-frequency induction heating, vacuumizing, bottom blowing argon, and casting molding. 
     The intermediate-frequency induction melting furnace is vertical, of which the bottom is a furnace base  2 , and of which the inside is a furnace chamber  3 ; a working table  6  is provided at the bottom of the furnace chamber  3 , a graphite melting crucible  7  is placed on the working table  6 , an intermediate-frequency induction heater  8  is provided around the outside of the graphite melting crucible  7 , the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite melt  9  is placed in the graphite melting crucible  7 ; a gas outlet tube  4  is provided at the upper right side of the intermediate-frequency induction melting furnace  1  and is controlled by an gas outlet valve  5 ; an argon tank  15  which is provided with an argon tube  16  and an argon valve  17  is provided at the left side of the intermediate-frequency induction melting furnace  1 ; the argon tube  16  connects a bottom blowing motor  11  which connects a bottom blowing tube  12 ; the bottom blowing tube  12  passes through the furnace base  2  and the working table  6  and enters into the graphite melting crucible  7 , so as to achieve bottom blowing smelting for the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite melt  9 ; a vacuum pump  13  is provided at a lower right side of the furnace base  2  and is communicated with the furnace chamber  3  through a vacuum tube  14 ; an electric cabinet  18  is provided at a right side of the intermediate-frequency induction smelting furnace  1 ; a display screen  19 , an indicator light  20 , a power switch  21 , an intermediate-frequency heat controller  22 , a bottom blowing motor controller  23  and a vacuum pump controller  24  are provided on the electric cabinet  18 ; the electric cabinet  18  connects the intermediate-frequency induction heater  8  through a first cable  25  and connects the bottom blowing motor  11  and the vacuum pump  13  through a second cable  26 ; and argon  10  is filled in the furnace chamber  3  in which the pressure is controlled by the gas outlet tube  4  and the gas outlet valve  5 . 
     A diffraction intensity pattern of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite is shown in  FIG. 2 . Major peak shown in  FIG. 2  is α-Al matrix, secondary peak shown in  FIG. 2  is silicon carbide and aluminum-copper-iron quasicrystal I phase. 
     A metallographic structure micrograph of the aluminum-copper-iron quasicrystal and silicon carbide mixed reinforced aluminum matrix composite is shown in  FIG. 3 . As shown in  FIG. 3 , the aluminum-copper-iron quasicrystal and the silicon carbide powders are in compact combination with α-Al matrix grain boundary, so that there are non-apparent aggregation phenomenon and less porosity defect after adding aluminum-copper-iron quasicrystal and silicon carbide powders.