KR101254569B1 - Fe-Mn solid solution strengthened high temperature aluminum alloys and Manufacturing Method Thereof - Google Patents

Abstract

The present invention relates to a Fe-Mn high-temperature high-strength reinforced heat-resistant aluminum alloy, characterized in that the alloying elements of iron (Fe) and manganese (Mn) in aluminum to form a high-temperature solid solution strengthening phase, the heat-resistant aluminum according to the present invention The alloys form a thermally solid solution with each other, and the thermally conductive solidified phase formed without a solid solution with aluminum, which is a base metal, reacts with aluminum even at a high temperature of 300 ° C. or higher, so that it does not coarsen or phase-degrade.

Iron, Manganese, Electrolytic Solid, Heat Resistant Aluminum Alloy

Description

Fe-Mn solid solution strengthened high temperature aluminum alloys and Manufacturing Method Thereof}

The present invention relates to a heat-resistant aluminum alloy, and more particularly, to the Fe-Mn electrification-employed reinforced heat-resistant aluminum alloy stable in high temperature by adding iron (Fe) and manganese (Mn) as an alloying element to an aluminum base, and a method of manufacturing the same. It is about.

In general, heat-resistant aluminum alloys developed to date are phase transformations of Al-Si-transition intermetallic compounds or Al-X (Fe, Fe, Cr, Mn, Ti) intermetallic compounds from liquid to solid phase on aluminum and aluminum alloy bases. By controlling the dispersion in the form of the precipitated phase formed in the solid phase through the crystallized phase and heat treatment formed during phosphorus solidification to implement the heat resistance characteristics.

However, the alloy that has improved the heat resistance characteristics by the crystallization and precipitation of the intermetallic compound on the aluminum and aluminum alloy base as described above has a problem that the heat resistance properties are deteriorated in an environment of 200 ℃ or more.

1 is a conceptual diagram showing the high temperature behavior of the elements added to the conventional heat-resistant aluminum alloy, as shown in the conventional heat-resistant aluminum alloy to maintain the thermodynamic equilibrium of the precipitated and precipitated intermetallic compound is maintained for a long time at 200 ℃ or more In order to form a new intermediate phase by reacting with a known aluminum, or coarsening of intermetallic compounds, there is a problem that occurs the generation and transition of the crack, this is because the heat-resistant properties are deteriorated is limited to use in the environment above 200 ℃.

Meanwhile, in the case of an aluminum composite material, nitrides, borides, oxides, and carbides are dispersed in a reinforced phase on the base of an aluminum alloy to realize heat resistance characteristics. The aluminum matrix composite material has better heat resistance than the heat resistant alloy using an intermetallic compound.

However, these aluminum matrix composites are difficult to control the reinforcement phase uniformly, and there is no price competitiveness in the composite materials using powder, and the characteristics of the aluminum matrix composites are drastically when an interfacial reaction occurs between the base metal aluminum and the aluminum alloy and the reinforcement phase. There is an underlying problem that is degraded.

That is, the above-described intermetallic compound and composite material-reinforced phase control heat-resistant alloy has a problem in that the heat-resistant property of the heat-resistant alloy is rapidly deteriorated as the intermetallic compound or the reinforcement phase exhibits heat resistance at high temperature of 200 ° C. or more. There was this.

In addition, most commercial aluminum alloys, including heat-resistant aluminum alloys developed to date, contain more than 10 additive elements. Therefore, when recycling aluminum alloys, active screening is difficult due to unnecessary reaction between aluminum and the additive elements. Because of this, there are restrictions on recycling.

The present invention is to solve the above problems,

Fe-Mn electrified tempered reinforced heat-resistant aluminum alloy that uses iron (Fe) and manganese (Mn) as an alloying element to form a stable reinforcement phase that does not coarsen or phase-degrade when reacted with aluminum as a base metal even at high temperatures It is an object to provide a manufacturing method.

In addition, the present invention is stable even at high temperature up to 200 ℃ as well as 1245 ℃, and provides a Fe-Mn electrified employment-enhanced heat-resistant aluminum alloy having a reinforcement phase that differs from the specific gravity with aluminum by 2.8 times, and a method of manufacturing the same The purpose.

According to an aspect of the present invention,

An alloy element of iron (Fe) and manganese (Mn) in aluminum provides an electrothermal solid-solution strengthening heat-resistant aluminum alloy, which is characterized in that it is combined.

In addition, the present invention is to add Fe (Mn) and manganese (Mn) as an alloying element to the molten aluminum molten aluminum in order to manufacture the Fe-Mn thermally strengthening reinforced heat-resistant aluminum alloy, or in the form of a Fe-Mn mother alloy After addition, when the alloying element is dissolved, the present invention provides a method for producing a Fe-Mn electrified employment-enhanced heat-resistant aluminum alloy, which is produced by casting.

As described above, in the Fe-Mn electrification-employment enhanced heat-resistant aluminum alloy according to the present invention, iron (Fe) and manganese (Mn) form an electrified solid with each other, and the electrothermal modulus formed without a solid solution with aluminum as a base metal The solid solution strengthening phase has innovative heat resistance characteristics that do not coarsen or phase-degrade by reacting with aluminum even at a high temperature of 300 ° C or higher.

In addition, since the Fe-Mn electrification-employment reinforced heat-resistant aluminum alloy according to the present invention is stable even at high temperatures up to 1245 ° C, it is applicable to diesel engine blocks in which aluminum alloys, which are light alloys, cannot be applied at 200 ° C or higher due to the limitation of heat-resistant aluminum. By maximizing the weight reduction effect, it is possible to pursue the fuel efficiency improvement by raising the heat resistance limit of the currently used car engine, and the melting point of the electrified solid formed of iron (Fe) and manganese (Mn) is about twice that of aluminum. Its specific gravity is 2.8 times higher than that of aluminum, and it can be applied to various fields in an environmentally-friendly manner based on the characteristic that it can actively select alloy elements of aluminum, iron (Fe) and manganese (Mn) during recycling. have.

Hereinafter, the present invention will be described in more detail.

Figure 2 is a conceptual diagram showing the stable high temperature behavior of the alloying elements added to the Fe-Mn electrification employment-enhanced heat-resistant aluminum alloy according to the present invention, while the present invention forms the electromechanical solid solution on the aluminum base as shown in FIG. It is related with the Fe-Mn conductivity-enhanced heat-resistant aluminum alloy that does not decompose or coarsen even at high temperatures by adding iron (Fe) and manganese (Mn).

In the Fe-Mn electrified employment-enhanced heat-resistant aluminum alloy according to the present invention, the alloying elements of iron (Fe) and manganese (Mn) are combined with aluminum to form a temporal solid solution strengthening phase.

The alloy elements iron (Fe) and manganese (Mn) are elements that form a tremor solid solution, and form a thermodynamically stable tremor solid phase strengthening phase present in a single phase.

Therefore, the strengthening phase of the iron (Fe) and manganese (Mn), the strengthening phase (hereinafter, Fe-Mn tremor solid) solid phase is present as a stable strengthening phase that does not react with aluminum at all at a high temperature of more than 200 ℃ because the reinforced phase is not decomposed or coarsened And, even when heated to the melting point of aluminum, there is a stable presence of the solid-solution solid formed in the aluminum, even if the re-melting the Fe-Mn conductivity-enhanced heat-resistant aluminum alloy prepared according to the present invention can be stably formed a solid-state solid solution strengthening phase formed , This can be confirmed through the experimental results described below.

On the other hand, the total of the alloying elements is preferably contained 0.5% to 10% by weight relative to aluminum. This is because when the total amount of the alloying elements is less than 0.5% by weight with respect to aluminum, the amount of alloying elements contained is not sufficient, so the reinforcing effect of the Fe-Mn conductivity solid solution is less. Coarse and coarsened reinforcements can cause castability and segregation problems.

In addition, iron (Fe) and manganese (Mn) constituting the alloying elements are not limited to the mixing ratio because they are the elements forming the tremor solid solution, iron (Fe) in the total alloying elements in the present invention 10 ~ 90 More preferably, 90% to 10% by weight of manganese (Mn) is included.

On the other hand, the modulus solidified solid phase is characterized in that to maintain a stable compound of the modulus solids at a temperature up to 1245 ℃, which is a Fe-Mn tremor solidified phase as a single phase at a temperature and remelting more than 300 ℃ through the experiment described below It can be confirmed that it exists and is stable.

The Fe-Mn electrified tempered reinforced heat-resistant aluminum alloy according to the present invention is added to the molten aluminum molten aluminum in the form of an alloy element of iron (Fe) and manganese (Mn), respectively, or in the form of a Fe-Mn mother alloy After the melting of the alloying element is preferably produced by casting, wherein the temperature of melting the aluminum is preferably made at 700 ℃ 30 ~ 40 ℃ higher than the melting point of aluminum 660 ℃ in consideration of heat loss.

Here, the Fe-Mn master alloy can be manufactured using various melting methods commonly used, but using plasma arc as a heat source, plasma arc melting method (Plasma Arc Melting, PAM) that can be dissolved in a wide range from low vacuum to atmospheric pressure Or melting and heating the metal conductor by Joule heat, which is caused by the eddy current of the coil in the opposite direction to the current of the coil due to the electromagnetic induction action. More preferably, it is prepared by easy vacuum induction melting (MnIM).

In addition, the total of the alloying elements is more preferably added to 0.5% by weight to 10% by weight relative to aluminum, which is segregation due to the coarsening of the Fe-Mn electrolytic solid-solid reinforcement phase of the heat-resistant aluminum alloy prepared through the manufacturing method It has been described above to the extent that it can exert its reinforcing effect while preventing.

Further, iron (Fe) and manganese (Mn) added as the alloying elements are not limited to the mixing ratio because they are the elements forming the solid-state solid solution, iron (Fe) in the total alloying elements in the present invention 10 ~ 90 More preferably, 90% to 10% by weight of manganese (Mn) is added.

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Hereinafter, the following experiments were conducted to prove the effect of the Fe-Mn electrification employment-enhanced heat-resistant aluminum alloy according to the present invention.

First, Figure 3 is a diagram showing a binary state diagram of Fe-Mn, as shown in the iron (Fe) and manganese (Mn) forms an electric solid solution to each other, the electrical conductivity formed to 1245 ℃ higher than the melting point of aluminum 660 ℃ It was confirmed that the solid solution exists stably in solid state.

In other words, it can be seen that the Fe-Mn electrified employment-enhanced heat-resistant aluminum alloy according to the present invention maintains a single phase even at a temperature about 2 times higher than the melting point of aluminum, and shows stability through this, and thus 1245 ° C. It can be easily applied to diesel engine blocks by utilizing the characteristics that coarsening and decomposition of Fe-Mn electrolytic solid-solution strengthening phase does not occur even at high temperature.

≪ Example 1 >

The aluminum molten aluminum melted at 700 ° C. was added to iron (Fe) and manganese (Mn) by 1.5 wt%, respectively, at 700 ° C., and then iron (Fe) and manganese (Mn) were added. After maintaining for about 30 minutes to 60 minutes to dissolve all, and cast to prepare a specimen of a heat-resistant aluminum alloy.

Figure 4 shows an optical microscope histology of observing the microstructure of the specimen prepared in Example 1, after polishing the specimen with SiC Emery paper # 200, 400, 600, 800, 1000, 1500, 2400, After micropolishing using Al ₂ O ₃ 1㎛ powder, the structure was observed by an optical microscope. Through the heat-resistant aluminum alloy according to the manufacturing method of the present invention through Figure 4 is a facet (Facet) of 30-50 ㎛ size It was confirmed that the reinforcement phase of the shape exists.

FIG. 5 shows the results of mapping the microstructure of the specimen prepared in Example 1 to an Electron Probe Micro-Analyzer (EPMA). The facet-reinforced phase identified in FIG. 4 is a Fe-Mn electrolytic solid solution. I could confirm that.

The following is to confirm the high temperature stability of the Fe-Mn electrification employment-enhanced heat-resistant aluminum alloy according to the present invention, after the specimen prepared in Example 1 was heat-treated at 300 ℃ for 200 hours, the microstructure of the heat-treated specimen The results observed with an optical microscope are shown in FIG. 6.

As shown in FIG. 6, the reinforcing phase made of the Fe-Mn electrolytic solid solution has the same facet shape as the microstructure shown in FIG. 4, unlike the existing intermetallic compound in which coarsening or phase decomposition occurs in an aluminum matrix at high temperature. The coarsening and phase decomposition of the reinforcement phase were not observed, and thus the Fe-Mn tremor solid-solution solidified phase of the Fe-Mn tremor employment tempered aluminum alloy according to the present invention was found to be stable at 300 ° C.

Figure 7 is a photograph of the microstructure of the specimen prepared by re-melting the specimen prepared in Example 1 by optical microscopy, where the specimen melted after re-melting the specimen prepared in Example 1 melting point of aluminum After remelting until casting.

 As shown in FIG. 7, the electrified solid formed in the Fe-Mn electrification-employment-reinforced heat-resistant aluminum alloy according to the present invention is not coarsened or decomposed at all during remelting, as is expected in the state diagram shown in FIG. It was confirmed that the phase was maintained, and that the characteristics and the specific gravity of the Fe-Mn electrolytic solids were 2.8 times or more than that of aluminum, the base metal aluminum and the alloy elements iron (Fe) and alloys were recycled when the heat-resistant aluminum alloy was recycled. Manganese (Mn) is expected to be used to actively sort and recycle to the level of eco-friendly virgin.

<Example 2>

The molten aluminum melted at 700 ° C. using a Plasma arc melting method at a temperature of 700 ° C., and the Fe-Mn matrix prepared so that the iron (Fe): manganese (Mn) ratio was 50% by weight to 50% by weight. The Fe-Mn master alloy added after the alloy was added to the molten metal by 0.5 wt%, 1 wt%, 3 wt%, 5 wt%, 7 wt%, 9 wt%, 10 wt% and 11 wt%, respectively. After maintaining about 30 minutes to 60 minutes until complete dissolution, and cast to prepare a specimen of a heat-resistant aluminum alloy.

FIG. 8 is a graph showing the average size of the electrolytic solid solution according to the content of alloying elements added to each specimen prepared in Example 2. Image of the microstructure of each specimen prepared in Example 2 measured by optical microscope Using an analyzer, the average size of the electrifying solids was measured according to each content (0.5 wt%, 1 wt%, 3 wt%, 5 wt%, 7 wt%, 9 wt%, 10 wt%, 11 wt%).

As a result, when the 0.5 wt% Fe-Mn mother alloy was added, the amount of the emulsified solid formed was small, and the size of the emulsified solid was found to be less than 5 μm. You can see that it is too coarse. Therefore, in the Fe-Mn electrified employment-enhanced heat-resistant aluminum alloy according to the present invention, when the content of the alloying element added to the aluminum is 0.5% by weight to 10% by weight, a sufficient amount of the electrolytic solution is formed to exert the effect as an alloy. It can be predicted that problems such as segregation due to the coarsening of the size can be prevented from occurring.

1 is a conceptual diagram showing the high temperature behavior of elements added to a conventional heat-resistant aluminum alloy.

Figure 2 is a conceptual diagram showing the stable high temperature behavior of the alloying elements added to the Fe-Mn electrification employment-enhanced heat-resistant aluminum alloy according to the present invention.

Figure 3 is a diagram showing a binary system state diagram of Fe-Mn.

Figure 4 is an optical microscope histology of observing the microstructure of the specimen prepared in Example 1.

Figure 5 is a photograph showing the results of mapping the microstructure of the specimen prepared in Example 1 with an Electron Probe Micro-Analyzer (EPMA).

6 is a photograph of the specimen prepared in Example 1 after the heat treatment at 300 ℃ for 200 hours, the microstructure of the heat-treated specimen with an optical microscope.

Figure 7 is a photograph of the microstructure of the specimens cast after remelting the specimen prepared in Example 1 by optical microscope.

Figure 8 is a graph showing the average size of the electrification solid solution according to the content of the alloying elements added to each specimen prepared in Example 2.

Claims (9)

delete The alloying elements of iron (Fe) and manganese (Mn) are combined to form an electrifying solidified phase on the aluminum base, The total amount of the alloying elements is Fe-Mn electrified employment-enhanced heat-resistant aluminum alloy, characterized in that containing 0.5% by weight to 10% by weight relative to the aluminum base. The method according to claim 2, Iron-Fe is 10 ~ 90% by weight, the manganese (Mn) 90 to 10% by weight in the total alloying elements Fe-Mn electrified employment-enhanced heat-resistant aluminum alloy. The method of claim 3, The electrified solid-solution reinforced phase has a heat-resistant property even at a temperature up to 1245 ℃, characterized in that formed in a facet shape (Facet) of the size of 30 ~ 50μm Fe-Mn electrification employment-enhanced heat-resistant aluminum alloy. In order to manufacture the Fe-Mn electrification-employment reinforced heat-resistant aluminum alloy of claim 2, iron (Fe) and manganese (Mn) were respectively added as alloy elements or added in the form of a Fe-Mn master alloy to the molten aluminum molten aluminum. Thereafter, when the alloying element is dissolved, the method for producing the Fe-Mn electrified employment-enhanced heat-resistant aluminum alloy, which is manufactured by casting. The method of claim 5, The Fe-Mn master alloy is a method of manufacturing a Fe-Mn conductivity-enhanced heat-resistant aluminum alloy, characterized in that produced by plasma arc melting (Plasma Arc Melting, PAM) or vacuum induction melting (MnaFeum Induction Melting, MnIM). delete delete The method according to any one of claims 5 to 6, 10 to 90% by weight of iron (Fe) and 90 to 10% by weight of manganese (Mn) are added to all the alloying elements.

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