CN1232665C - High porosity through hole multi-porous aluminum alloy, preparation method and special apparatus thereof - Google Patents

Abstract

The present invention discloses a preparation method of a through hole multiporous aluminum alloy with high porosity. Firstly, an aluminium alloy is heated to the melting point, the temperature of the aluminium alloy melt is kept between 660 and 750 DEG C, and filler particles are loaded into a mold, and insulated at a temperature of 500 to 660 DEG C until the temperature of the filler particles are uniform. The rest accounts for 5 to 20% of the theoretical casting amount of the aluminium alloy, the mold is placed on the base of a sucking disk on a negative-pressure apparatus, the insulated aluminium alloy melt is cast in the mold, the mold is communicated with the negative-pressure apparatus with the pressure of -40 to -2 KPa, and a composite body of the filler particles and the aluminium alloy is taken out and the filler particles are removed after the aluminium alloy is solidified. The present invention also discloses a through hole multiporous aluminum alloy with high porosity, and the porosity of the multiporous aluminum alloy is 70 to 95%. In addition, the present invention discloses an apparatus for preparing the through hole multiporous aluminum alloy with high porosity. The multiporous aluminum alloy with the porosity of 70 to 95%, which is obtained by the method, has a through hole degree of 20 to 35%.

Description

Method and device for manufacturing high-porosity through-hole porous aluminum alloy

1. Technical field

The invention relates to the field of metal material processing, in particular to a method and device for manufacturing high-porosity through-hole porous aluminum alloys.

2. Background technology

In the process of preparing porous aluminum alloy by the negative pressure infiltration method, due to the limitation of the bulk volume fraction of filler particles (45%-60%), the additional porosity (Pr< 5%) and the porosity (Pr<5%) produced by the solidification and shrinkage of the aluminum alloy, the porosity of the obtained porous aluminum alloy is 55% to 70%. So far there is no reliable method for preparing porous aluminum alloys with high porosity (70%-95%).

3. Contents of the invention

Technical Problem The present invention provides a method and device for manufacturing a high-porosity through-hole porous aluminum alloy.

Technical Solution A method for manufacturing high-porosity through-hole porous aluminum alloys, including the following steps: the first step is to weigh a certain quality of aluminum alloy, which is the actual casting quality of aluminum alloy, and heat it to melt to keep the aluminum alloy The temperature of the melt is 660°C-750°C, the filler particles are put into the mold 1, and the temperature of the filler particles is kept at 500°C-660°C until the temperature of the filler particles is uniform, wherein: actual casting quality of aluminum alloy = theoretical casting quality of aluminum alloy + margin, Theoretical aluminum alloy casting quality = height of filler particle accumulation × cross-sectional area of filler particle accumulation × aluminum alloy density × (1-porosity of porous aluminum alloy), and the balance accounts for 5% to 20% of the theoretical aluminum alloy casting amount. The second step is to place the mold 1 on the suction cup base 2 of the negative pressure device 3, and then cast the heat-preserved aluminum alloy melt 4 into the mold 1, and connect the mold 1 to a negative pressure with a pressure of -2KPa～-40KPa Device 3, the aluminum alloy melt penetrates into the filler particles, and a part of the aluminum alloy melt flows through the upper bottom plate 6 and stays between the upper bottom plate 6 and the lower bottom plate 7, and the third step is to take out the filler particles after the aluminum alloy is solidified Composite with aluminum alloy, remove the filler particles, get a porosity of 70% to 95%, the shape of the pores is polygonal or spherical, the pores are evenly distributed, the average pore diameter is 0.5 to 7mm, and the through hole is 20% to 35%. High porosity through-hole porous aluminum alloy.

A special device for manufacturing high-porosity through-hole porous aluminum alloys, including a negative pressure system and a mold, one end of the mold is connected to the negative pressure system, and an upper bottom plate and a lower bottom plate are placed in the mold, wherein the upper bottom plate is a grid Barbed wire with a side length of 2-6mm, the lower bottom plate is an orifice plate with a hole diameter of 2-6mm and 100-200 mesh barbed wire.

Technical effects (1) The present invention controls the seepage velocity of the aluminum alloy melt by controlling the temperature of the aluminum alloy melt, the temperature of the filler particles and the seepage negative pressure, so that the aluminum alloy melt flows through the filler particles at a certain seepage velocity, so that The interstices of the filler particles are uniformly but not sufficiently filled by the aluminum alloy melt. Since the gaps of the filler particles are not fully filled, but uniformly filled, the obtained porous aluminum alloy has a higher porosity. (2) In the process of preparing a porous aluminum alloy with a porosity of 70%-95% (such as 70%, 75%, 78%, 80%, 85%, 90%, 95%), if the casting amount of the aluminum alloy is too small, The liquid aluminum will choose a better seepage path during the seepage process, and the gaps between the filler particles will not be filled evenly, so a porous aluminum alloy with an uneven skeleton will be obtained; adding a certain margin can effectively increase the uniformity of the porous aluminum alloy , to obtain a porous aluminum alloy with high through-hole and uniform skeleton; the remainder will flow through the upper bottom plate of the mold, and finally solidify and stay between the upper bottom plate and the lower bottom plate. Different porosities require different margins. According to the different porosity requirements of porous aluminum alloys, the present invention pre-estimates the allowance and calculates the required quality of aluminum alloys to obtain porous aluminum alloys with uniform skeletons. (3) Usually, the diameter of the circular hole connecting two adjacent holes in the porous aluminum alloy is called the diameter of the through hole of the porous aluminum alloy, denoted as L, and the degree of interconnection between adjacent holes in the porous aluminum alloy is called is the through-hole degree of the porous aluminum alloy, denoted as ω, that is: $\mathrm{\&omega;}=\frac{L}{\mathrm{D.}}.$ The through hole of the 70%-95% porous aluminum alloy obtained by the invention reaches 20%-35%. (4) The through-hole porous aluminum alloy with high porosity has good sound-absorbing performance, and the porous aluminum alloy with a porosity of 70% to 95% can be used as sound-absorbing material in some specific sound frequency ranges. (5) Porous aluminum alloy can be regarded as a special case of two-phase coexistence of aluminum alloy matrix and air. The inhomogeneity of the two phases of the air phase and the aluminum alloy skeleton and the stress-strain phase difference are the physical reasons for the high damping. The damping characteristics are related to the pore structure parameters of the porous aluminum alloy. Increasing the porosity and reducing the pore diameter will increase the internal friction value of the porous aluminum alloy. Therefore, the porous aluminum alloy with a porosity of 70% to 95% has excellent damping performance. (6) Porous aluminum has unique structural characteristics. On the one hand, the thermal conductivity of the gas inside the hole is poor, and the radiation is reduced through the repeated reflection and absorption of the cell wall, so it has a small thermal conductivity. increased by the increase. At the same time, under the condition of forced convection, the through-hole porous aluminum alloy shows good heat dissipation characteristics due to the strong convection of the gas in the internal pores, and its heat dissipation characteristics increase with the increase of porosity. Therefore, porous aluminum alloys with a porosity of 70% to 95% can be used as thermal insulation materials under natural convection conditions, and used as heat dissipation components under forced convection conditions. Compared with porous aluminum alloys with lower porosity, they have more Strong heat insulation and heat dissipation performance; (7) The pores of the porous aluminum alloy are interconnected and distributed in a three-dimensional network skeleton, with good permeability. The specific fluid permeability is related to the porosity, pore size, fluid viscosity, flow rate and so on. The transmission coefficient α depends on the structural characteristics of the porous aluminum alloy, and increases with the increase of the pore diameter and porosity. The porous aluminum alloy with a porosity of 70% to 95% provided by the invention is a good material for filtration and fluid control, and can also be used as a catalyst carrier. (8) The function of the upper bottom plate in the present invention is to allow the excess of the cast aluminum alloy to pass through, so that the porosity of the porous aluminum alloy is uniform. (9) The bottom plate of the present invention adopts an orifice plate pasted with large-mesh barbed wire to prevent the aluminum alloy liquid from flowing into the negative pressure device without affecting the effect of the negative pressure.

4. Description of drawings

Fig. 1 is the figure of negative pressure seepage device of the present invention

Fig. 2 is a mold structure diagram of the present invention

Fig. 3 is a schematic diagram of the upper base plate of the present invention

Fig. 4 is a schematic diagram of the bottom plate of the present invention

Figure 5 is a porous aluminum alloy with a pore size range of 4.75-5.5mm and a porosity of 64.2%.

Fig. 6 is the porous aluminum alloy obtained by the present invention in the range of 2.25-3.5 mm in diameter and 74.8% in porosity

Fig. 7 is the porous aluminum alloy obtained by the present invention in the range of 4.75-5.5 mm in diameter and 84.7% in porosity

Figure 8 is a porous aluminum alloy with a pore diameter range of 5.5-6.8mm and a porosity of 90.4% obtained by the present invention

V. Specific implementation plan

Example 1 A method for manufacturing a high-porosity through-hole porous aluminum alloy, comprising the following steps: first, weigh a certain quality of aluminum alloy (the aluminum alloy can be an aluminum-silicon alloy containing 6% to 11% silicon or an aluminum-silicon alloy containing Copper 4-10% aluminum-copper alloy), the quality is the actual aluminum alloy casting quality, heat it to melt, keep the aluminum alloy melt temperature at 660°C-750°C, the temperature can be 660°C, 680°C, 700°C ℃, 750℃, put the filler particles into the mold 1, keep warm at 500℃～660℃ until the temperature of the filler particles is uniform, the temperature can be 500℃, 550℃, 600℃, 620℃, 640℃, 660℃, where : Actual aluminum alloy casting quality = theoretical aluminum alloy casting quality + margin, theoretical aluminum alloy casting quality = filler particle accumulation height × filler particle accumulation cross-sectional area × aluminum alloy density × (1-porous aluminum alloy porosity), The balance accounts for 5% to 20% of the theoretical aluminum alloy casting amount, which can be 5%, 7%, 10%, 15%, and 20%. The second step is to place the mold 1 on the suction cup base 2 of the negative pressure device 3 , and then cast the heat-preserved aluminum alloy melt 4 into the mold 1, and connect the mold 1 to the negative pressure device 3 with a pressure of -2KPa～-40KPa, the negative pressure can be selected as -2KPa, -4KPa, -6KPa, -8KPa, -10KPa, -20KPa, -30KPa, -40KPa, the aluminum alloy melt penetrates into the filler particles, and part of the aluminum alloy melt flows through the upper bottom plate 6 and stays between the upper bottom plate 6 and the lower bottom plate 7. Three steps, after the aluminum alloy is solidified, take out the composite body of filler particles and aluminum alloy, remove the filler particles, and obtain 70%-95% porous aluminum alloy.

Example 2 A high-porosity through-hole porous aluminum alloy obtained by the method described in Example 1 (the aluminum alloy can be an aluminum-silicon alloy containing 6% to 11% of silicon or an aluminum-copper alloy containing 4 to 10% of copper) , its porosity is 70% to 95%, the porosity can be 70%, 75%, 78%, 80%, 85%, 90%, 95%, the shape of the pores is polygonal or spherical, the pores are evenly distributed, and the average pore size 0.5-7mm, can be 0.5mm, 1.0mm, 3mm, 5mm, 7mm, and the through hole can reach 20%-35%.

Example 3 A special device for manufacturing high-porosity through-hole porous aluminum alloys used in the method described in Example 1, including a negative pressure system 3 and a mold 1, one end of the mold 1 is connected to the negative pressure system 3, and inside the mold 1 An upper base plate 6 and a lower base plate 7 are placed, wherein the upper base plate 6 is a barbed wire mesh with a grid side length of 2 to 6 mm, and the side length can be 2 mm, 4 mm, and 6 mm, and the lower base plate 7 is pasted with 100 to 200 meshes (which can be 100 mesh, 150 mesh, 200 mesh) the hole diameter of the barbed wire is 2-6mm orifice plate, the hole diameter can be 2mm, 4mm, 6mm.

Claims (3)

1. a method of making through-hole porous aluminium alloy with high porosity is characterized in that comprising the steps:

The first step, take by weighing the aluminium alloy of certain mass, this quality is actual aluminium alloy casting quality, be heated to thawing, keeping the aluminium alloy melt temperature is 660 ℃～750 ℃, filler grain is packed in the mould (1), under 500 ℃～660 ℃, be incubated even to the filler grain temperature, wherein: actual aluminium alloy casting quality=theoretical aluminium alloy casting quality+surplus, theoretical aluminium alloy casting quality=filler grain accumulation body height * filler grain accumulation body cross-sectional area * aluminium alloy density * (1-porous Al alloy porosity), 5%～20% of the reasonable opinion of surplus aluminium alloy casting amount

Second step, mould (1) is placed on the sucker base (2) of negative pressure device (3), aluminium alloy melt (4) after will being incubated again is cast in the mould (1), and with mould (1) be communicated in pressure for-2KPa～-negative pressure device (3) of 40KPa, aluminium alloy melt infiltrates in the filler grain, and some aluminium alloy melt flows through upper plate (6), rests between upper plate (6) and the lower shoe (7)

The 3rd step, treat aluminum alloy solidification after, take out the complex body of filler grain and aluminium alloy, remove filler grain, obtain porosity and be 70%～95%, mean pore size is that 0.5～7mm, through hole degree are 20%～35% through-hole porous aluminium alloy with high porosity.

2. the method for manufacturing through-hole porous aluminium alloy with high porosity according to claim 1 is characterized in that void shape is polygon or sphere.

3. device that is used for the manufacturing through-hole porous aluminium alloy with high porosity of the described method of claim 1, comprise negative pressure system (3) and mould (1), one end of mould (1) is connected in negative pressure system (3), it is characterized in that being placed with in the mould (1) upper plate (6) and lower shoe (7), wherein, upper plate (6) is that the grid length of side is the wire netting of 2～6mm, and lower shoe (7) is 2～6mm and the orifice plate that posts 100～200 order wire nettings for the aperture.

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