RU2359780C1 - Method of receiving of cast composition material - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to foundry. Method includes heating of matrix alloy higher the liquidus temperature, introduction in it reinforcing particles material in the form of powder, blending of melt of matrix alloy with keeping during 1-15 minutes. Before introduction of reinforcing particles on melt seat they are evenly mixed with shaving or powder of uniform or close by content to composition of matrix alloy in correlation from 1:100 up to 1:10.

EFFECT: it is achieved increasing of distribution uniformity of introduced into melt reinforcing particles.

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Description

The invention relates to foundry, metallurgy and materials science, in particular to methods for producing cast composite materials with a metal matrix reinforced with dispersed solid particles with special properties.

Many methods are known for producing composite materials with a metal matrix by dissolving, kneading, impregnating, self-dispersing reinforcing particles by producing endogenous particles, etc.

1. "Theory and technology of cast composite materials." Gavrilin I.V. The dissertation for the degree of Doctor of Technical Sciences. St. Petersburg: St. Petersburg Technical University. 1991. 340 s

2. “Composite materials obtained by impregnation”. Tuchinsky L.I. M .: Metallurgy, 1986, p. 70-87.

3. "Casting partially hardening alloys." Flemings M.K., Merabyan R.E. Per. from English Materials of the 4th international foundry congress. M.: Mechanical Engineering, 1974, p. 78-87.

A common drawback of all these methods is the insufficient uniformity of the distribution of reinforcing particles in the matrix up to the presence of clusters - agglomerates, including hundreds and thousands of particles, which makes the properties of such composites unstable.

The technical result achieved by the implementation of the invention is to increase the uniformity of the distribution of the reinforcing particles introduced into the melt and, as a result, to improve the quality of the alloy.

This technical result is achieved by the method of producing cast composite materials, including heating the matrix alloy above the liquidus temperature, introducing the metal of the reinforcing particles in the form of powder into it, mixing the melt of the matrix alloy with exposure for 1-15 minutes, while before introducing the reinforcing particles onto the melt mirror they are uniformly mixed with chips or powder of the same or similar composition to the composition of the matrix alloy in a ratio of 1: 100 to 1:10.

Reinforced particles in the form of powder when mixed with chips are evenly distributed on the rough surface of the chip in 1-2 layers. Thus, the reinforcing particles are evenly distributed evenly over the surface of the chips before entering the melt. Particles are held on the surface of the chip by friction, adhesion and cohesion. When a chip of a composition of the same or similar composition as a matrix alloy is introduced into the melt, it is easily wetted, assimilated and dissolved in the melt, entraining evenly distributed reinforcing particles, wetting them and introducing them into the melt. Chips or powder coated with reinforcing particles play the role of a carrier of reinforcing particles, facilitating their input and uniform distribution into the melt.

The method has the following differences:

- dispersed reinforcing particles are pre-mixed uniformly with shavings or powder of an alloy of the same or similar composition as the melt into which the reinforcing particles are to be introduced;

- dispersed reinforcing particles are mixed with chips or powder in a ratio of 1: 100 to 1:10;

- a mixture of chips or powder with reinforcing particles is introduced into the melt on the mirror.

The method is simple and effective, does not require special temperatures and special equipment, is easily applicable in any foundry and metallurgical shops.

An example of the method

The proposed method for producing cast composite alloys with a carrier of reinforcing particles in the form of chips or powder of the same composition as the matrix alloy was carried out as follows. To obtain composite material in a crucible furnace, part of the solid charge of one of the cast aluminum alloys was first melted. The alloy was overheated 50-150 ° C above the liquidus temperature (the temperature in this method is not particularly significant).

Dry chips of the same composition as the matrix alloy were uniformly mixed manually with reinforcing particles of silicon carbide in a ratio of 1: 100 to 1:10.

A mixture of the carrier (shavings or powder) with reinforcing particles was fed in portions directly to the mirror of the matrix melt in the furnace with a layer of 5-10 cm and the mixture was slightly melted into the melt with a hand foundry tool. Then the shavings (or powder) spontaneously dissolved (melted). If necessary, a mixture of particles with a carrier was introduced several times, achieving the required concentration of particles in the melt.

After entering the carrier with particles, the alloy was overheated to the discharge temperature and kept for 1-15 minutes in the furnace using manual or induction mixing. Then, the finished composite was poured into molds.

Data on the homogeneity of the obtained cast composite material in comparison with the known method are shown in table 1. The uniformity criterion is the percentage of reinforcing particles distributed individually in the matrix (without accumulations), in comparison with the total number of particles in the matrix. The number of individually located particles was calculated by the known method of securing solid finished composite on microsections using a MIM-8 microscope.

Table 1 A method of obtaining a composite material The homogeneity criteria of the composite material with the ratio of reinforcing particles and shavings (powder), (%) 1: 100 1:70 1:50 1:30 1:20 1:10 1: 5 100: 1 1. The method of obtaining a carrier 78 89 70 61 44 eighteen 10 - 2. The known method - - - - - - - 8

From the table it follows that the proposed method provides a significantly higher uniformity of the distribution of reinforcing particles in the matrix compared with the known method.

Using a ratio of reinforcing particles to chips> 1: 100 (for example, 1: 200) is impractical due to the low concentration of reinforcing particles in the composite (less than 1%). With a ratio <1:10 (for example, 1: 5), the effect of increasing uniformity is not achieved.

Therefore, the technical result of the invention is the achievement of a high uniformity of the distribution of reinforcing particles in the matrix of the composite material achieved.

Claims (1)

A method for producing cast composite materials, including heating the matrix alloy above liquidus temperature, introducing reinforcing metal particles into it in powder form, mixing the alloy of the matrix alloy with exposure for 1-15 minutes, while before introducing the reinforcing particles onto the melt mirror they are uniformly mixed with chips or powder of the same or similar composition to the composition of the matrix alloy in a ratio of 1: 100 to 1:10.