KR100222068B1 - Hybrid composites and method for making same - Google Patents

Abstract

The present invention provides SiCw (SiC Whisker) and SiC _p (SiC particles) by simultaneously adding and strengthening particles and whisker-reinforced hybrid composite materials having excellent strength, elongation and wear resistance, and at low cost, and a method of manufacturing the same. It is about.

The method for producing the particles and the whisker-reinforced hybrid composite material of the present invention is Cu: 3.8-3.9% by weight, Mg: 1.2-1.8% by weight, Mn: 0.3-0.9% by weight, Fe: 0.14-0.3% by weight, Si: 0.2 After mixing SiC _p (SiC particles) uniformly in the A1 matrix alloy powder consisting of up to% by weight, Zn: up to 0.25% by weight, and the remaining amount of A1, SiC _w : SiC _p is (3-1 ): SiC _w (SiC Whisker) is mixed to make (1-3) so that (SiC _w + SiC _p ) / A1 matrix powder is 10-25 vol.%, And the mixed powder is 30-60 minutes in methanol aqueous solution is mixed to prepare a composite powder, and then the obtained composite powder is charged into a can (Can), degassed and vacuum-sealed while heating up to 500 ℃, and then the composite powder encapsulated in the can Hot press molding at a pressure of 100-120 MPa at 510-540 ° C., followed by extrusion at an extrusion ratio of (10-30): 1 at 430-470 ° C. The.

In addition, the particles of the present invention and whisker-reinforced hybrid composite material, Cu: 3.8-3.9% by weight, Mg: 1.2-1.8% by weight, Mn: 0.3-0.9% by weight, Fe: 0.14-0.3% by weight, Si: 0.2% by weight SiC _w : SiC _p was mixed as (3-1): (1-3) to an A1 alloy matrix powder composed of% or less, Zn: 0.25 wt% or less, and a residual amount of A1, and (SiC _w + SiC _p ) is 10-25% by volume.

Description

Particle and Whisker Reinforced Hybrid Composites and Manufacturing Method Thereof

The present invention relates to a hybrid composite material, and more particularly, by adding SiC _w (SiC Whisker) and SiC _p (SiC particles) at the same time to strengthen, excellent strength, elongation and wear resistance characteristics and low manufacturing cost A particle and whisker reinforced hybrid composite material and a method for producing the same.

In general, SiC _w has better strength and elongation characteristics than SiC _p but is expensive and harmful to the human body, while SiC _p has lower strength and elongation characteristics than SiC _w , but has better wear resistance and lower manufacturing cost. The degree of harm to human body is much smaller than that of SiC _w .

Thus, SiC _w and SiC _p a at the same time, enhanced strength, elongation, abrasion resistance of the hybrid composite material is enhanced only conventional SiC _w and SiC _p alone because the physical characteristics, excellent surface in comparison to composites that economical aspect and Industry A breakthrough in application has been made.

The properties of Metal Matrix Composites depend on the properties of the added Reinforcements and the properties of the matrix material.

Ingot metallurgy and powder metallurgy can be roughly classified into manufacturing methods, and it is well known that the powder method has various mechanical properties better than the casting method, but the manufacturing process is complicated and expensive. There is this.

In particular, the excellent physical properties such as the amount SiC _w to be added when the addition of the expensive SiC _w to enhance the producing a composite material by a powder method of claim 20 volume (vol.)% By strength and elongation can be expected, but in the production There are also problems in the manufacturing technique, such that there is no breakage of the whiskers and uniform distribution of the added reinforcement phase.

In other words, the study on the evaluation of mechanical properties according to the method of manufacturing a composite material reinforced with only SiC _w alone has been conducted due to the fact that SiC _w is expensive, dispersion problem, and harmful to human body, despite its excellent strength characteristics. There is limited research going on.

In contrast, composite materials reinforced with only low-cost SiC _p added alone have excellent abrasion resistance, and are currently commercialized in the automobile field in the United States, and many studies have been made to commercialize them in Korea, and also in the manufacturing method. Many researches are underway to solve the problem of phase dispersion.

In particular, the wet method is mainly used in the production of a composite material reinforced with only SiC _w by powder method, while the dry method is mainly used in the production of a composite material reinforced with SiC _p alone.

This is because the wet method can minimize the damage of SiC _w during the manufacturing process compared to the dry method, and there are many problems to be studied.

Therefore, also in the manufacturing method, there is a difference between the composite material reinforced by adding SiC _w alone and the composite material reinforced by adding SiC _p alone, and the manufacturing cost also differs. Thus, the composite material reinforced by adding SiC _w and SiC _p simultaneously Very little research has been done on.

Accordingly, the present invention has been made to solve the above-described problems of the prior art, and is excellent in strength, elongation and wear resistance, and low in manufacturing price, so as to make full use of the advantages of SiC _w and additionally obtain the advantages of SiC _p . It is an object to provide a particle and whisker reinforced hybrid composite material and a method of manufacturing the same.

1 is a graph showing the relationship between stress and strain obtained after high temperature torsional strain at 350 ° C.

2 is a graph showing the relationship between stress and strain obtained after high temperature torsional deformation at 450 ° C.

3 and 4 are micrographs showing the cross-sectional structure of the hybrid composite material obtained according to the present invention, respectively.

In order to achieve the above object, in the present invention, Cu: 3.8-3.9% by weight, Mg: 1.2-1.8% by weight, Mn: 0.3-0.9% by weight, Fe: 0.14-0.3% by weight, Si: 0.2% by weight or less, Zn After mixing SiC _p (SiC particles) uniformly in an A1 matrix alloy powder composed of 0.25 wt% or less and a residual amount of A1, SiCw: SiC _p is (3-1) :( 1-3 SiC _w (SiC Whisker) is mixed so that the (SiC _w + SiC _p ) / A1 matrix powder is 10-25% by volume, and the mixed powder is 30- in aqueous methanol solution. 60 minutes of mixing is made into a composite powder, and then the obtained composite powder is charged into a can, degassed and vacuum-sealed at a temperature of up to 500 ° C., and then the composite powder vacuum-sealed into the can is 100 at 510-540 ° C. Particle and whisker-reinforced hive, which is produced by hot pressing at a pressure of -120 MPa and then extruding at an extrusion ratio of (10-30): 1 at 430-470 ° C. It provides a method for producing de composites.

Moreover, in another aspect of this invention, Cu: 3.8-3.9 weight%, Mg: 1.2-1.8 weight%, Mn: 0.3-0.9 weight%, Fe: 0.14-0.3 weight%, Si: 0.2 weight% or less, Zn: SiCw: SiC _p is mixed with (3-1) :( 1-3) in an A1 alloy matrix powder consisting of 0.25 wt% or less and a residual amount of A1, so that (SiC _w + SiC _p ) is 10- A particle and whisker reinforced hybrid composite material having a volume of 25 vol.% Is provided.

Hereinafter, the particles and whisker reinforced hybrid composite material of the present invention and a manufacturing method thereof will be described in detail with reference to Examples.

In the method for producing the particles and the whisker-reinforced hybrid composite material of the present invention, A1 2124 powder having an average particle size of 44 μm or less was used as a known alloy, and SiC _w and SiC _p were used as the reinforcement phase.

First, by using a ceramic ball (alumina) ball-milling mixed with the base alloy and SiC _p for 48-72 hours to uniformly disperse the reinforcement phase in the base powder, and then additionally mixed SiC _w in methanol solution Mix SiC _w and SiC _p by (3-1) :( 1-3) so that (SiC _w + SiC _p ) is 10-25% by volume (vol.)% With respect to the known powder It was mixed to prepare a composite powder.

The methanol aqueous solution atmosphere is intended to minimize the breakage of SiC _w during manufacture.

Subsequently, the obtained composite powder was charged into A16063 cans having a relatively good fluidity in A1 can material, and degassed and vacuum-sealed at a temperature of 2-3 ° C. to 500 ° C. at 100 ° C. at 510-540 ° C. The composite material was prepared by hot pressing at a pressure of -120 MPa, followed by extrusion at an extrusion ratio of (10-30): 1 at 430-470 ° C.

In the method for producing the particles and whisker-reinforced hybrid composite material of the present invention described above, the ball mill time is set to a time sufficient to homogenize the distribution of the matrix powder and the reinforcement phase. For a total of 400 g of the sample (base powder + SiC _p ), the ball mill time is 48 hours or more. Is enough.

In addition, an aqueous methanol solution is used to minimize the damage of the whiskers during mixing as a wet atmosphere.

In the method of the present invention, the hot forming temperature is limited to 510-540 ° C. Preferably, the hot forming temperature is 502 ° C or more (about 40 ° C), which is the solidus temperature of the matrix structure. Various reaction products may deteriorate the mechanical properties, and if hot formed below the solidus temperature, not only the density of the molded body may be lowered, but also the whisker may be broken.

That is, press molding while the matrix structure itself maintains some liquid phase (20-30%) is necessary to minimize reaction products, maximize density and minimize whisker damage.

The pressing force is a pressure for obtaining a sufficient density of about 99.9%.

In the production method of the present invention, the extrusion temperature is set to 430-470 ° C. in a temperature range where the flowability of the molded body is the best, that is, a temperature range that does not cause extrusion defects. If too high, hot cracking occurs and is too low. If the extrusion pressure is too high, extrusion does not occur.

In addition, the extrusion ratio was set in the range of (10-30): 1 in consideration of whether the improvement of the mechanical properties by grain refinement can be expected after extrusion before extrusion.

The present invention also provides Cu: 3.8-3.9 wt%, Mg: 1.2-1.8 wt%, Mn: 0.3-0.9 wt%, Fe: 0.14-0.3 wt%, Si: 0.2 wt% Hereafter, SiCw: SiCp is mixed as (3-1) :( 1-3) to an Al alloy matrix powder composed of Zn: 0.25 wt% or less and the remaining amount of A1, whereby (SiCw + SiCp) is 10- A particle and whisker reinforced hybrid composite material having a volume of 25 vol.% Is provided.

The component composition range of the Al 2124 matrix powder used was Cu: 3.8-3.9% by weight, Mg: 1.2-1.8% by weight, Mn: 0.3-0.9% by weight, Fe: 0.14-0.3% by weight, Si: 0.2% by weight or less. , Zn: 0.25 wt% or less, and the remaining amount consists of Al.

The SiC _w used was 5-15 μm in length and 0.3-0.6 μm in diameter, and SiC _p was less than 1-10 μm.

Using the above-described materials, a hybrid composite material having a (SiC _w + SiC _p ) / A1 2124 of 10-25% by volume (vol.)% Was prepared, wherein the mixing ratio of SiC _w and SiC _p was (3-1): (1-3).

In the composite material of the present invention, the (SiC _w + SiC _p ) of 10-25% by volume (vol.)% Of the known powder is for the reinforcement phase to exhibit a relatively sufficient reinforcing effect in the known material. If it is 25% or more, the elongation is sharply lowered, which is a problem in actual commercialization. If it is 10% or less, the reinforcement effect cannot be sufficiently expected.

Hereinafter, the present invention will be described in more detail with reference to the embodiments.

EXAMPLE

In the hybrid composite material, (SiC _w + SiC _p ) was 15% by volume, and the SiC _w and SiC _p mixing ratios were changed to 1: 1, 1: 2, 1: 3 respectively. When the ratio is different, it is to examine in which case the best physical properties are obtained.

To evaluate the physical properties of this material, a high temperature torsional strain test was conducted with varying temperature and strain rate.

1 shows the relationship between stress and strain obtained after high temperature torsional strain. At 350 ° C, the composite material containing SiC _w alone shows the best stress value. Among hybrid composite materials, SiC _w : SiC _p is 1 In case of 1: 1, the best stress shade is shown.

However, FIG. 2, as shown, in the 450 ℃ SiC _w only added alone composite material and a SiC _w: was similar to the high-temperature stress values of the hybrid composite material is added to the 1: a SiC _p 1.

In addition, the high temperature stress of the hybrid composite material having SiC _w : SiC _p 1: 1 was better than that of other 1: 2 or 1: 3 hybrid composite materials and was higher than that of the composite material containing SiC _p alone. Showed.

3 and 4 are scanning electron micrographs of the extruded material extruded at an extrusion ratio of 20: 1 at 470 ° C. after hot forming, with SiC _w : SiC _p of 1: 1 (15 vol% in total). It can be seen that the whiskers are rearranged, and that SiC _w and SiC _p are relatively uniformly dispersed in the matrix.

It can be said that the higher the whisker's orientation after extrusion and the higher the dispersion between the whisker and the particles, the better the mechanical properties of the material.

In addition, it can be seen that SiC _p does not cause cracking during extrusion, and SiC _w may be observed to decrease somewhat during the manufacturing process.

Grain size was approximately 7 μm in the direction perpendicular to the extrusion direction.

Therefore, the hybrid composite material added with SiC _w : SiC _p = 1: 1 and the composite material added with SiC _w alone in the high temperature stress value when deformed at 450 ° C are similar to SiC _w which is expensive and harmful to health. It suggests the possibility of replacing a single composite material manufactured using the hybrid composite material.

Therefore, the particles and the whisker-reinforced hybrid composite material of the present invention as described above and a method for producing the same, compared to the composite material reinforced with only SiC _w or SiC _p alone, the physical properties and harmful to the human body is improved, the production price This reduction is useful in economic and industrial applications.

Claims (2)

Cu: 3.8-3.9% by weight, Mg: 1.2-1.8% by weight, Mn: 0.3-0.9% by weight, Fe: 0.14-0.3% by weight, Si: 0.2% by weight or less, Zn: 0.25% by weight or less, and the remaining amount of A1 SiC _p (SiC particles) is mixed with A1 matrix alloy powder composed of SiC _w (SiC whiskers) so that SiC _w : SiC _p is (3-1) :( 1-3). Whisker)) is mixed to make (SiC _w + SiC _p ) / A1 known powder 10-25 vol.%, And the mixed powder is mixed into an aqueous methanol solution for 30-60 minutes to prepare a composite powder. Subsequently, the obtained composite powder was charged into a can, degassed and vacuum sealed while heating to 500 ° C., and then the composite powder vacuum-sealed into the can was hot press-molded at a pressure of 100-120 MPa at 510-540 ° C. And then extruded at an extrusion ratio of (10-30): 1 at 430-470 ° C. to produce particles and whisker reinforced hybrid composite materials. Cu: 3.8-3.9% by weight, Mg: 1.2-1.8% by weight, Mn: 0.3-0.9% by weight, Fe: 0.14-0.3% by weight, Si: 0.2% by weight or less, Zn: 0.25% by weight or less, and the remaining amount of A1 SiC _w : SiC _p is mixed with (3-1) :( 1-3) in an A1 alloy matrix powder composed of (SiC _w + SiC _p ) with a volume of 10-25% by volume (vol.)% Of the matrix powder. Particle and Whisker Reinforced Hybrid Composites.

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