WO2006134405A1

WO2006134405A1 - Method of manufacturing aluminium-based composite material

Info

Publication number: WO2006134405A1
Application number: PCT/GE2006/000007
Authority: WO
Inventors: Paata Gogoladze; Vazha Chagelishvili
Original assignee: Paata Gogoladze; Vazha Chagelishvili
Priority date: 2005-06-16
Filing date: 2006-06-16
Publication date: 2006-12-21
Also published as: GEP20063997B; DE112006001603T5

Abstract

The present invention relates to the field of Metalurgy and, more particularly, it relates to the method of manufacturing an aluminium-based composite material that can be used in producing structural materials having certain advantageous properties. In accordance with the method, melt aluminium is subject to reinforcement with fibers, wherein basalt fibers having diameter of 16-18 micrometers are used as fibers, which are disposed on a crucible bottom in the form a layer having thickness of 8-10 millimeters whereupon an aluminium layer of the same volume is disposed. The crucible together with its content is brought into a furnace and subject to heating up to the temperatures of 8000C - 85O0C, and to stirring continuously for 10-15 minutes at these temperatures by use of a stirring means, the crucible being brought out of the furnace afterwards, and thus manufactured desired product being casted into moulds and cooled.

Description

Method of Manufacturing Aluminium-based Composite

Material

Description Field of application

The present invention relates to the field of Metallurgy and, more particularly, it relates to the method of manufacturing an aluminium-based composite material that can be used in producing structural materials having certain advantageous properties.

Background of the invention

Aluminium alloys and composite materials based thereon are currently extensively used in various fields of technology, such as machine building and aircraft building, in manufacturing household articles and the like, due to their specific properties. It should be noted that each individual case of application of a big veriety of applications found in industry requires different parameters of characteristics. For example, in producing aircraft elements, properties such as mechanical strength and high-temperature strength is of great importance so as to obtain good operational performance. Such properties are achieved by reinforcing the aluminium alloy containig magnesium, silicium, copper, manganese, iron and other admixtures with steel fibers as is described in one of the cited document RU 2243289 (IPC: C22C 47/20). According to the another cited document RU 2217522 (IPC: C22C 49/06), high stiffness, resistance and size stability is achieved by reinforcing the aluminium alloy matrix with successively arranged layers of carbonaceous fibers in parallel to a given direction. According to the yet another cited document SU 1624851 (IPC: B28B 1/52), basalt fibers of 3 millimeters diameter are subject to partitioning, mixing thereof with freshly precipitated gel of aluminium hydroxide, drying and burning at the temperatures in the range of from 500⁰C to 55O⁰C so as to produce a heat insulating product. Still another technology known in the art which is disclosed in the Russian application RU 98122445 (IPC: B32B 15/14) teaches that a detail for use in outer space applications is made of magnesium containing aluminium alloy composite material wherein continuous carbonaceous fibers having ultra high value of Young's modulus take 55-65% part of the volume. The most relevant to the present invention is a method for manufacturing composite materials reinforced with a fibrous material, which is disclosed in the Soviet Union patent document SU 602306 (IPC: B22F 3/26), comprising the steps of periodic feeding boron fibers separated by a separating means to the matrix metal - melt of aluminium of mark A7, forming a composite material and, subsequently, recovering it. However, each of the known technologies are disadvantageous in many respects. In particular, complicated facilities, expensive materials and complex technological steps are required for their implementation and, most importantly, the products manufactured by use of these technologies are lack of high hardness as is shown with the data provided in the cited documents.

Technical result

Thus the object and, respectively, the result of the present invention is provision of simplified method for manufacturing an aluminium-based high hardness composite material.

The method in accordance with the present invention is advantageous in that it does not require designing of special-purpose facilities and can be performed by apparatuses that are extensively utilized in technique.

Substance of the invention

The method in accordance to the present invention is performed in the following manner. On a crucible bottom, already made basalt fibers of 10-15 millimeters length and 16-18 micrometers diameter are arranged as a layer of selected thickness, e.g. 8-10 millimeters. Upon the layer, aluminium layer of approximately the same volume is disposed. The crucible together with its content is entered into a furnace and is subject to heating up to the temperatures in the range of from 800⁰C to 85O⁰C. Continuous stirring is performed during 10-15 minutes at the above mentioned temperatures by a stirring means whereupon the crucible is brought out of the furnace, the slag is removed from the desired product which is casted into a mould and cooled. In order to provide higher hardness, optimum content of the basalt in the composite material should be 9-13%, the content being easily regulable by changing the ratio of aluminium and basalt masses.

In accordance with one embodiment of the present invention, a number of pairs of fibers and aluminium layers are disposed in succession (one after another) in the crucible. In accordance with another embodiment of the present invention, a crucible made of cast iron or graphite can be utilized. Advantage of such crucibles is their cheapness and substantially lack of adhesiveness with the desired product.

In accordance with still another embodiment of the present invention, a stirring means and moulds made of stainless steel can be utilized. Advantage of such a stirring means and moulds is high durability.

The product manufactured in accordance with the present invention is characterized by high hardness. Conducted Brilell tests revealed the composite material to have the hardness substantially higher then that of starting aluminium. In particular, the obtained hardness value is at least eight times as much as that of starting material. Moreover, the manufactured product is substantially homogenous and its properties considerably depend on nature of interaction occuring between aluminium and basalt, hi results of analysis carried out by means of a microscope, the basalt fibers grains linked to the aluminium by numerous direct bonds can be seen. Presumably, this can be accounted for not only by physical diffusion of aluminium molecules into basalt but also by a chemical reaction, specifically, by recovery of oxides contained in the basalt with aluminium, i.e. substitution of metal atoms contained therein, such as magnesium, iron, manganese atoms, with atoms of aluminium. Next, the recovered metal atoms diffuse into the aluminium. As a result of close bonds, linkage between the aluminium and basalt becomes very strong which apparently contributes to the mechanical properties of the desired material in a positive manner. Presumably, good mechanical properties of the material according to the present invention are accounted for also by proximity between the densities of aluminium and basalt (their values, at the temperatures from 800⁰C to 85O⁰C, are in the range of from about 2.3gr/cm³ to about 2.8gr/cm³) and high homogenity which is achieved during the melting process at the time the composite material is subject to continuous stirring. It should be noted that sizes of the basalt grains, their influence on hardness and, also, mechanical properties of the manufactured product have not yet studied in full and further research to be conducted is required. Examples Example 1. hi the process of aluminium reinforcement, stirring of said content of said crucible lasts 10 minutes at the high temperatures (minimum of duration of the process in accordance with the present invention). Besides, the ratio of the basalt and alluminium masses is as little as possible (1 kilogram aluminium versus 0.1 kilogram basalt). Hardness of the manufactured product is lGpa. Example 2.

In the process of aluminium reinforcement, stirring of said content of said crucible lasts 10 minutes at the high temperatures (minimum of duration of the process in accordance with the present invention). Besides, the ratio of the basalt and alluminium masses is as big as possible (1 kilogram aluminium versus 0.15 kilogram basalt). Hardness of the manufactured product is l.βGpa. Example 3.

In the process of aluminium reinforcement, stirring of said content of said crucible lasts 15 minutes at the high temperatures (maximum of duration of the process in accordance with the present invention). Besides, the ratio of the basalt and alluminium masses is as little as possible (1 kilogram aluminium versus 0.1 kilogram basalt). Hardness of the manufactured product is 1.2Gpa. Example 4.

In the process of aluminium reinforcement, stirring of said content of said crucible 15 minutes at the high temperatures (maximum of duration of the process in accordance with the present invention). Besides, the ratio of the basalt and alluminium masses is as big as possible (1 kilogram aluminium versus 0.15 kilogram basalt). Hardness of the manufactured product is 1.9Gpa.

The results set out in the above examples show that the manufactured product retains high hardness with variations of parameter values within the limits stipulated by the present invention.

Although this invention has been described based on its exemplary embodiments which are the most utilitarian and preferable ones, it will be readily appreciated that the above embodiments have been described for illustrative purposes only, and are not limiting. Many other variations, modifications and improvements are possible in the exemplary embodiments without departing from the scope of this invention.

Claims

1. A method of manufacturing an aluminium-based composite material, which comprises reinforcing melt aluminium with fibers, characterized by: using as said fibers basalt fibers having diameters of from 16 micrometers to 18 micrometers; disposing said basalt fibers onto a crucible bottom in the form of a layer; disposing a layer of aluminium material having volume approximately the same as that of said fibers onto said layer of fibers; bringing said crucible together with said content into a furnace; heating said crucible together with said content up to the temperatures in the range of from 800⁰C to 85O⁰C; continuously stirring said content of said crucible during 10-15 minutes at said temperatures; casting the manufactured desired product into moulds upon bringing said crucible out of said furnace; and cooling said product.

2. A method in accordance with claim 1, characterized in that said fibers and aluminium are disposed in said crucible as a number of pairs of said fibers and aluminium layers arranged one after another.

3. A method in accordance with claims 1 and 2, characterized in that said crucible is made of cast iron.

4. A method in accordance with claims 1 - 3, characterized in that said crucible is made of graphite.

5. A method in accordance with claims 1 - 4, characterized in that said stirring is performed by a stirring means made of stainless steel.

6. A method in accordance with claims 1 - 5, characterized in that said moulds are made of stainless steel.