TWI648410B - Method for fabricating aluminum-fly ash composite material - Google Patents

Abstract

Aluminum-based fly ash castings produced by the manufacturing methods disclosed by the prior art generally have excessive pores or pores, resulting in a decrease or poor mechanical properties. In view of this, the present invention provides a method of manufacturing an aluminum-based fly ash composite. The manufacturing method of the present invention specifically completes the coarse ash screening and the fine screening treatment of the fly ash by means of a floating sieve and a magnetic sieve, and then batch-adds the preheated fly ash into the molten aluminum substrate. Finally, the aluminum melt mixed with fly ash is processed into an aluminum-based fly ash casting by a die immersion quick-solid method. Moreover, experimental data shows that the method of manufacturing the aluminum-based fly ash composite proposed by the present invention does contribute to reducing the porosity of the aluminum-based fly ash casting and maintaining or enhancing its mechanical properties.

Description

Aluminum-based fly ash composite material manufacturing method

The present invention relates to the technical field of aluminum-fly ash (ALFA) composite materials, and more particularly to a method for manufacturing an aluminum-based fly ash composite material capable of reducing internal pores and enhancing mechanical properties.

A metal matrix composite (MMC) is produced by solid-solving at least one reinforcing phase material into a base phase metal or an alloy thereof. Wherein, the reinforcing phase material is mostly an inorganic non-metal material, such as ceramic (ie, metal oxide), carbon, germanium, graphite, and boron. In 1993, Pradeep K. Rohatgi chemically reacted with an aluminum substrate such as SiO ₂ and Fe ₂ O ₃ contained in fly ash from coal-fired waste, thereby producing alumina (Al ₂ O ₃ ) as The strengthening phase of the aluminum substrate, and then the Fly-Ash-Containing Aluminum Matrix Composites.

With the continuous advancement of material manufacturing technology, the current process technology of aluminum-based fly ash composites mainly includes Pressure infiltration, Powder metallurgy and Composing. Among them, the composite casting method is currently widely used in the manufacture of aluminum-based fly ash composite materials because of its low process cost. The literature first reveals the related technology of manufacturing aluminum-based fly ash composite materials by composite casting method. Here, the literature refers to: Zhuang Shuiwang et al., “The influence of process 參數 on the uniformity of fly ash in aluminum-based fly ash composites”, Journal of Foundry Engineering, Vol. 39, No. 1 (2013 / 03 / 01), P22 - P28. According to the literature 1, we can know that the existing aluminum-based fly ash composite manufacturing process includes the following steps: Step (1): Select the F-class fly ash specified in the American Standards Testing Association (ASTM) C618-12a standard specification. The X-ray Diffraction (XRD) shows that the fly ash comprises: 52.73% SiO ₂ , 26.87% Al ₂ O ₃ and 5.11% Fe ₂ O ₃ ; Step (2): The fly ash is sieved to screen fly ash having a particle size between 53 μm and 106 μm; step (3): pickling fly ash to remove impurities thereof; step (4): Japanese Industrial Specification (Japanese Industrial) Standards, JIS) is an ADC6 aluminum alloy, wherein the chemical composition of the ADC6 aluminum alloy comprises: 0.45% Si, 3.15% Mg, 0.31% Fe, 0.17% Mn, and 89.39% Al; Step (5): placing the fly ash in a high temperature furnace and preheating to 800 ^o C; Step (6): placing the ADC6 aluminum alloy in a high frequency melting furnace and heating to 700 ^o C to melt the ADC6 aluminum The alloy becomes an aluminum melt; step (7): the aluminum melt is stirred at 500 rpm using a stirring device, and during the stirring process The preheated fly ash is added to the aluminum melt at a flow rate of 0.2 g/sec; Step (8): Mold Immersed Rapid Solidification Process (MIRSP) is used to mix the fly ash The aluminum melt soup is processed into an aluminum-based fly ash casting.

The inventor of the present invention found that based on the research experience of aluminum-based fly ash composite materials for many years, the above steps (1) to (8) can obtain aluminum-based fly ash castings having a hardness of up to 58.13 Burgundy hardness (BHN). The process still shows the following practical shortcomings: (1) The density, shape and particle size of the fly ash particles will affect the dispersibility of the fly ash particles in the aluminum melt soup. A large amount of one-time addition will cause the fly ash to be in the aluminum melt soup. The phenomenon of clustering causes the SiO ₂ , Al ₂ O ₃ and Fe ₂ O ₃ and oxides contained in the fly ash to be difficult to react with the aluminum melt; (2) According to the above point 1, the oxide and the aluminum melt soup Insufficient reaction between the two ultimately results in the resulting aluminum-based fly ash casting having too many voids or pores, resulting in a decrease in the mechanical properties of the aluminum-based fly ash casting.

As apparent from the above description, how to design and manufacture an aluminum-based fly ash casting capable of producing low porosity and to effectively improve it has become a very important issue. In view of this, the inventors of the present invention have vigorously studied and created, and finally developed a method for manufacturing the aluminum-based composite material of the present invention.

Aluminum-based fly ash castings produced by the manufacturing methods disclosed by the prior art generally have excessive pores or pores, resulting in a decrease in mechanical properties. Accordingly, it is a primary object of the present invention to provide a method of making an aluminum-based fly ash composite. In the manufacturing method of the present invention, the fly ash is roughly sieved and finely sieved by a floating sieve and a magnetic sieve, and then the preheated fly ash is batch-added into the molten aluminum substrate, and finally reused. The die immersion quick-solid method processes the aluminum melt mixed with fly ash into an aluminum-based fly ash casting. Moreover, experimental data shows that the method of manufacturing the aluminum-based fly ash composite proposed by the present invention does contribute to reducing the porosity of the aluminum-based fly ash casting and maintaining or enhancing its mechanical properties.

In order to achieve the above-mentioned main object of the present invention, the inventor of the present invention provides an embodiment of the method for manufacturing the aluminum-based fly ash composite material, which comprises the following steps: (1) preparing fly ash and an aluminum substrate; Performing a preliminary screening treatment on the fly ash to select fly ash having a particle size between 53 μm and 106 μm; (3) performing a pretreatment on the fly ash to remove impurities; (4) The fly ash is subjected to a fine screening treatment to remove the fly ash having a higher iron content; (5) performing a high temperature baking treatment on the fly ash to burn off impurities and unburned carbon in the fly ash; 6) placing the fly ash into a preheating device and preheating to 600-800 ° C; (7) placing the aluminum substrate into a metal melting device and heating to 700-800 ° C to make the aluminum substrate (a) agitating the aluminum melt using a stirring device, and adding the preheated fly ash to the aluminum melt at a flow rate of 0.05-0.15 g/sec during the stirring; (9) The aluminum fused soup mixed with fly ash is processed into an aluminum base by Mold Immersed Rapid Solidification Process (MIRSP) Fly ash castings.

In the embodiment of the method for manufacturing the aluminum-based fly ash composite material of the present invention, in the step (7), a magnesium material may be placed in the metal melting device together with the aluminum substrate, and heated. Up to 700-800 ^o C melts the magnesium material and the aluminum substrate into the aluminum melt.

In the embodiment of the method for manufacturing the aluminum-based fly ash composite material of the present invention, in the step (8), the preheated fly ash is added to the aluminum melt soup based on a specific batch number. And the specific number of batches is at least two times. Moreover, during the execution of the step (8), it is necessary to wait for the previous batch of fly ash to complete the reaction with the aluminum melt, and then add the next batch of fly ash to the aluminum melt soup.

In order to more clearly describe a method of manufacturing an aluminum-based fly ash composite material proposed by the present invention, a preferred embodiment of the present invention will be described in detail below with reference to the drawings.

1A and 1B are flow charts showing a method of manufacturing an aluminum-based fly ash composite material of the present invention. 1A and FIG. 1B, it is known that an aluminum-based fly ash composite material having low porosity and excellent mechanical properties is to be produced by the method for manufacturing the aluminum-based fly ash composite material, and the first step (S1) is performed on the flow. : Prepare fly ash and an aluminum substrate. Continuing, the manufacturing method of the present invention is followed by the step (S2) of performing a preliminary screening treatment on the fly ash to screen fly ash having a particle size between 53 μm and 106 μm. Please also refer to the perspective view of the primary screening device shown in FIG. 2 and the detailed flow chart of the step (S2) shown in FIG. Specifically, the present invention completes the step (S2) in a floating screen manner, which includes the following detailed steps: Step (S21): Preparing a preliminary screening device 2, wherein the primary screening device 2 includes a container 20 and a setting a first screen 21 and a second screen 22 in the container 20; and the first screen 21 is disposed higher than the second screen 22, and the screen of the first screen 21 The mesh aperture size is larger than the mesh aperture size of the second screen 22; Step (S22): the fly ash is poured into the container 20, and flowing water is injected into the container 20, and the fly ash is washed with flowing water. And step (S23): the flowing water is discharged from the container 20 through a drain raft 23 of the container 20, and the fly ash having a particle size of between 53 μm and 106 μm is sieved out of the first screen 21 and Between the second screens 22.

It must be emphasized that conventional techniques usually use a screening machine to screen the fly ash. However, it usually takes a certain time (for example, 45 minutes) to screen the fly ash material from 53 μm. Fly ash between 106 μm. Differently, the present invention designs the primary screening device 2 and flushes the fly ash with flowing water. Such a preliminary screening process can select fly ash having a particle size between 53 μm and 106 μm from the fly ash raw material within 5 minutes. In addition, it is necessary to particularly emphasize that the present invention does not particularly limit the kind of the aluminum substrate, and may be a Die-casting aluminum alloy containing a magnesium component, for example, an ADC6 specified by Japanese Industrial Standards (JIS). Aluminum alloy, ADC10 aluminum alloy and ADC12 aluminum alloy. In addition, material engineers familiar with the design and manufacture of aluminum alloys should know that ZL-based aluminum alloys are also cast aluminum alloys containing magnesium components, such as ZL101, ZL103, ZL105, ZL108, ZL109, ZL301, ZL305, and the like. On the other hand, the fly ash used in the present invention is a Class F fly ash specified by the American Society for Testing and Materials (ASTM) C618-12a standard specification, and it is determined that it contains various components listed in the following Table (1): Table 1)  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> SiO₂</td><td> Al₂O₃</td><td> Fe₂O₃</td><td> Loss on ignition (Loss On ignition, LOI) </td></tr><tr><td> 58.9% </td><td> 25.5% </td><td> 4.93% </td><td> 4.1% </ Td></tr></TBODY></TABLE>

Continuing, the flow of the manufacturing method is followed by step (S3): a pre-treatment of the fly ash to remove impurities thereof. Fly ash pretreatment refers to the surface treatment of fly ash to increase its cleanliness while also improving the wettability between the fly ash particles and the liquid phase substrate. In the step (S3) of the present invention, the fly ash is first washed with an acidic solution, and then the acid washed fly ash is washed with pure water. After the completion of the step (S3), the step (S4) is subsequently performed: a fine screening treatment is performed on the fly ash to remove the fly ash having a higher iron content. It is worth noting that the step (S3) is to wash the fly ash with an acidic solution and pure water, respectively. Therefore, the fly ash obtained after the completion of the step (S3) is in a wet state like a mud, and cannot be directly subjected to fine screening treatment. For this reason, before the step (S4) is performed, a low-temperature baking treatment must be performed on the fly ash to remove moisture.

In the step (S4), the fly ash is first screened by using a high frequency oscillating screening machine with a screen having a mesh size of 53 μm, and a magnetic magnet is used to magnetically treat the fly ash. This method absorbs fly ash with a high iron content. After the completion of the step (S4), the manufacturing method of the present invention then performs the step (S5): performing a high-temperature baking treatment on the fly ash to burn off impurities and unburned carbon in the fly ash. After the completion of the step (S5), it is determined that the fly ash contains various components listed in the following Table (2): Table (2)  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> SiO₂</td><td> Al₂O₃</td><td> Fe₂O₃</td><td> Loss on ignition (Loss On ignition, LOI) </td></tr><tr><td> 68% </td><td> 26.9% </td><td> 2.9% </td><td> 0.2% </ Td></tr></TBODY></TABLE>

The comparison table (1) and the table (2) can be easily found that the fly ash obtained after the preliminary screening treatment, the pretreatment, the fine screening treatment, and the high temperature baking treatment is completed as compared with the fly ash which has not been subjected to any treatment process. The loss on ignition (LOI) and the iron oxide component are greatly reduced; on the contrary, the alumina and cerium oxide components contained in the fly ash are improved. After completion of high temperature baking step of the manufacturing method of the present invention is then performed based step (S6) to said ash preheating means placed in a preheated to 600-800 ^o C, and then performing step (S7) to Step (S8). 4A and 4B are schematic diagrams showing processes of steps (S7) to (S8). 4A, the aluminum substrate is placed in a metal melting apparatus 3, and heated to 700-800 ^o C so that the aluminum substrate into a molten metal 31 of aluminum. Further, as shown in FIG. 4A, a stirring device 5 is used to stir the aluminum melt 31, and the fly ash feeding device 4 is used to complete the preheating fly at a flow rate of 0.05-0.15 g/sec during the stirring process. Ash is added to the aluminum melt 31. Finally, as shown in FIG. 4B, the present invention processes the aluminum melt soup 31 mixed with fly ash into an aluminum-based fly ash casting by a Mold Immersed Rapid Solidification Process (MIRSP).

It must be additionally noted that the present invention uses an aluminum alloy containing a magnesium component as the aluminum substrate; even so, in order to increase the wettability between the fly ash and the aluminum substrate, in the step (S7) , I may be a magnesium aluminum substrate with the material placed in the metal melting apparatus 3, and heated to 700-800 ^o C so that the magnesium and the aluminum base material with a so-called molten aluminum melt Soup 31. It is worth emphasizing that the inventor of this case based on years of research experience in aluminum-based fly ash composites found that adding a large amount of fly ash into the aluminum melting soup 31 at one time would cause fly ash to be in the aluminum melting soup 31. The phenomenon of clustering occurs, and it is difficult for SiO ₂ , Al ₂ O _{3 ,} and Fe ₂ O ₃ and oxide contained in the fly ash to react with the aluminum melt 31. Therefore, in this step (S8), the preheated fly ash is added to the aluminum melt 31 based on a specific batch number, and the number of batches is at least twice. Further, when the fly ash is batch-added, it is necessary to wait for the previous batch of fly ash to complete the reaction with the aluminum melt 31, and then add the next batch of fly ash to the aluminum melt 31.

It must be additionally explained that, in the step (S9), the aluminum melt 31 mixed with the magnesium material and the fly ash is poured into the mold 6 (as shown in FIG. 4B), and the aluminum is first sprinkled. The surface of the base fly ash casting was cooled for about 30 seconds; then, the aluminum-based fly ash casting was shaped and removed, and the aluminum-based fly ash casting was immediately cooled with running cooling water for 1 minute.

Experimental example

In the case of the existing aluminum-based fly ash composite, it usually contains 1-5 wt% of magnesium component, 3-15 wt% of fly ash and 96-83 wt% of aluminum substrate. Therefore, in the experimental example of the present invention, an aluminum alloy of ADC10 was used as the aluminum substrate, and the addition amount of the fly ash and the magnesium material was predetermined to be 15 wt% and 2 wt%, and the number of batches of fly ash was set to three times. Briefly, the preheated fly ash is added to the aluminum melt soup in three batches, and the amount added per batch is 6 wt%, 6 wt%, and 3 wt%.

Fig. 5 is a graph showing the amount of fly ash added relative to the density, and Fig. 6 is a graph showing the amount of fly ash added relative to the porosity. From the experimental data of FIG. 5 and FIG. 6, it can be seen that the aluminum-based fly ash with two batches of added (6 wt% + 6 wt%) fly ash is compared with the aluminum-based fly ash casting with fly ash added at a time of 6 wt%. The casting system shows a lower porosity. Please continue to refer to Figure 7, which shows a data plot of the amount of fly ash added versus hardness. It can be seen from the experimental data of FIG. 7 that the aluminum-based fly ash casting having a fly ash added at a time of 6 wt%, the aluminum-based fly ash casting having two batches of added (6 wt% + 6 wt%) fly ash, and having three batches A secondary (6 wt% + 6 wt% + 3 wt%) fly ash-based aluminum fly ash casting, all of which have a hardness higher than 85 Boar hardness (BHN).

Thus, the above-described system has completely and clearly explained the flow of steps of a method for producing an aluminum-based fly ash composite material of the present invention; and, as apparent from the above, the present invention has the following advantages:

(1) Aluminum-based fly ash castings produced by the manufacturing method disclosed in the prior art (such as Document 1) have excessive pores or pores, resulting in a decrease in mechanical properties of the aluminum-based fly ash casting. Compared with the conventional manufacturing method, the method for manufacturing the aluminum-based fly ash composite material proposed by the present invention is particularly characterized in that the fly ash is coarsely sieved and finely sieved by a floating sieve and a magnetic sieve, and then the preheating is completed. The fly ash is batch-added into the aluminum substrate in a molten state, and finally the aluminum melt mixed with fly ash is processed into an aluminum-based fly ash casting by a die-dipping method. Moreover, experimental data shows that the method of manufacturing the aluminum-based fly ash composite proposed by the present invention contributes to reducing the porosity of the aluminum-based fly ash casting and maintaining or enhancing its mechanical properties.

It is to be understood that the foregoing detailed description of the embodiments of the present invention is not intended to Both should be included in the scope of the patent in this case.

<present invention>

S1-S9‧‧ steps

2‧‧‧Primary screening device

20‧‧‧ container

21‧‧‧First screen

22‧‧‧Second screen

23‧‧‧Drainage

S21-S23‧‧‧Steps

3‧‧‧Metal melting device

31‧‧‧Aluminium melt soup

5‧‧‧Agitator

6‧‧‧Mold

4‧‧‧ fly ash feeding device

<知知>

no

1A and 1B are flow charts showing a method of manufacturing an aluminum-based fly ash composite material of the present invention; Fig. 2 is a perspective view showing a preliminary screening device; Fig. 3 is a detailed flow chart showing the step (S2); 4B is a schematic view showing a process of the steps (S7) to (S8); FIG. 5 is a data chart showing the amount of fly ash added relative to the density; and FIG. 6 is a data chart showing the amount of fly ash added relative to the porosity; The 7 series shows a data plot of the amount of fly ash added relative to the hardness.

Claims (10)

The invention relates to a method for manufacturing an aluminum-based fly ash composite material, comprising the steps of: (1) preparing fly ash and an aluminum substrate; (2) performing a preliminary screening treatment on the fly ash, and the particle size is between 53 μm to Fly ash between 106 μm; (3) pre-treatment of the fly ash to remove impurities; (4) using a high-frequency oscillating screening machine with a screen having a pore size of 53 μm mesh The ash is subjected to a fine screening treatment; (5) the high temperature baking treatment is performed on the fly ash to burn off impurities and unburned carbon in the fly ash; (6) placing the fly ash into a preheating device Preheating to 600-800 ° C; (7) placing the aluminum substrate into a metal melting device and heating to 700-800 ° C to make the aluminum substrate an aluminum melt; (8) using a stirring The apparatus stirs the aluminum melt, and adds the preheated fly ash to the aluminum melt at a flow rate of 0.05-0.15 g/sec during the stirring; and (9) using the mold dip-solid method (Mold Immersed) Rapid Solidification Process (MIRSP) processes aluminum fused soup mixed with fly ash into an aluminum-based fly ash casting. The method for producing an aluminum-based fly ash composite material according to claim 1, wherein the aluminum base material is a Die-casting aluminum alloy containing a magnesium component. The method for manufacturing an aluminum-based fly ash composite material according to claim 1, wherein the step (2) comprises the following detailed steps: (21) preparing a container and setting a first sieve in the container a mesh and a second screen; wherein the first screen is disposed higher than the second screen, and the screen size of the first screen is larger than the screen size of the second screen (22) pouring the fly ash into the container, injecting flowing water into the container, flushing the fly ash with flowing water; and (23) discharging the flowing water from the container through a drain of the container, Fly ash having a particle size between 53 μm and 106 μm is screened between the first screen and the second screen. The method for producing an aluminum-based fly ash composite material according to claim 1, wherein the step (3) comprises the following detailed steps of: washing the fly ash with an acidic solution; and rinsing the fly ash with pure water. . The method for manufacturing an aluminum-based fly ash composite material according to claim 1, wherein the step (4) and the step (5) further comprise the step of: using the strong magnet to perform the fly ash. A magnetic treatment removes fly ash with a high iron content. The method for manufacturing an aluminum-based fly ash composite material according to claim 1, wherein in the step (8), the preheated fly ash is added to the aluminum melt soup based on a specific batch number. And the specific number of batches is at least two times. The method for manufacturing an aluminum-based fly ash composite material according to claim 5, wherein in the step (8), after waiting for the reaction of the previous batch of fly ash and the aluminum melt, The next batch of fly ash is then added to the aluminum melt. The method for manufacturing an aluminum-based fly ash composite material according to claim 1, wherein in the step (7), a magnesium material is placed in the metal melting device together with the aluminum substrate. And heating to 700-800 ° C causes the magnesium material to melt with the aluminum substrate into the aluminum melt. The method for manufacturing an aluminum-based fly ash composite material according to claim 1, wherein the step (3) and the step (4) further comprise the step of: performing a low-temperature drying on the fly ash. Bake to remove moisture. The method for manufacturing an aluminum-based fly ash composite material according to claim 8, wherein the metal magnesium, the fly ash, and the aluminum substrate account for 1-5 wt% of the aluminum-based fly ash castings, respectively. %, 3-15 wt% and 96-83 wt%.