US3055763A

US3055763A - Metal-aggregate product

Info

Publication number: US3055763A
Application number: US747600A
Authority: US
Inventors: Jack R Kreigh; Gibson James Keith
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-07-10
Filing date: 1958-07-10
Publication date: 1962-09-25
Anticipated expiration: 1979-09-25

Description

United States Patent ()fiice 3,055,763 Patented Sept. 25, 1962 3,055,763 METAL-AGGREGATE PRODUCT Jack R. Kreigh and James Keith Gibson, both of R0. Box 445, La Salle, Ill. No Drawing. Filed July 10, 1958, Ser. No. 747,600 5 Claims. (Cl. res-41) This invention relates to improvements in a product comprising metal and an aggregate, the product being characterized in that the metal has a lower melting point than the aggregate and carries the aggregate as discrete pieces embedded more or less uniformly in a matrix of the metal.

This unique product comprising the present invention is composed of a metal or metal alloy in which is embedded, more or less uniformly, an aggregate so selected as to impart desired characteristics to the resulting mass, the metallic content of the mass being in the continuous or external phase.

By the proper selection of the aggregate and percentages thereof various characteristics may be imparted to the resulting mass, that is, its specific gravity may be varied; its strength-to-Weight ratio may be varied; its handling ability may be varied, that is, it may be so constituted as to be readily sawn or received nails or screws or other fastening means; its heat or electrical conductivity may be varied and in general the mass may be made to differ materially from the metal or metal alloy in its unmixed state.

Although substantially any metal or metal alloy may be employed in this invention, the lower melting point metals, that is, those having a melting point of about 700 C. or below, or alloys thereof, such as, lead, zinc, tin, aluminum and magnesium appear to oifer the greatest possibilities, and we prefer aluminum and magnesium or alloys thereof since extremely light-weight products and products having high strength-to-weight ratios may be made.

Aggregates of many types may be employed limited generally by the qualification that they have a melting point above the melting point of the metal with which they are used, and will not appreciably dissolve or disintegrate when mixed with the molten metal, as will be hereinafter described. Preferably the aggregate comprises a nonmetallic mineral material. Thus, for aluminum or magnesium or the alloys thereof, mineral aggregates, such as vermiculite (Zonolite), perlite, ground refractories, fired clay pellets or the like have been successfully used. Aggregates such as those enumerated may also be used with other metals since they do not melt or disintegrate at the molten temperatures of the metals contemplated.

In incorporating the aggregate in the metal, the selected metal may be melted in a suitable receptacle and the aggregate may be introduced therein and, with or without the addition of heat, the mass may be vigorously mixed to uniformly disperse the aggregate particles in the metal mass. While the mixing is continued the mass may be permitted to cool until the metal reaches a viscous state at which time the mixing is discontinued and the mass permitted to solidify with the aggregate embedded therein. When the metal reaches the viscous state mentioned herein before, the aggregate particles will not tend to stratify in the metal mass. If desired, before the mass solidifies, and while it is still in a relatively flowable, although viscous, condition, it may be poured into a suitable mold wherein it is permitted to solidify. Or, if desired, before the mass completely solidifies, and while stratification of the aggregate is inhibited, it may be passed through a conventional extrusion die to form desired extruded shapes.

The resulting mass is particularly characterized in that the aggregate particles are substantially unmelted or unfluxed and exist in the metal matrix as substantially uniformly distributed discrete particles and are related to the metal mass not unlike the aggregate in the usual cement-concrete mixture.

As an example of control which may be exercised over the metal-aggregate product by the proper selection and proper proportions of aggregate to metal, 2 parts of vermiculite was mixed with 1 part of an aluminum alloy, by volume. During the mixing operation the metal originally introduced at 1275 F. cooled to about 1070 F. at which time the metal was sufliciently viscous as to prevent segregation or stratification. The resulting mass had a specific gravity of less than 1, that is, it would float on water. The aluminum alloy remained in the continuous or external phase. The product was not a sponge material, that is, it contained no voids, as such, but appeared as a "virtual solid comprising the metal and the uniformly embedded vermiculite particles.

As another example of control which may be exercised over the metal aggregate product by the proper selection and proper proportions of aggregate to metal, 1 /2 parts of fired clay pellets was mixed with 1 part of an aluminum-magnesium alloy, by volume. During the mixing operation the metal originally introduced at 1325' F. cooled to about 1070 F., at which time the metal was sufficiently viscous as to prevent segregation or Stratification. The resulting mass had a specific gravity of more than 1 but less than the specific gravity of the alloy used. The alloy remained in the continuous or external phase.

It is desirable that the aggregate be in such condition as not to inhibit the wetting of its surfaces by the metal. Hence, it is desirable that the aggregate be dry and carry no surface moisture or oil surface film.

The product comprising the present invention, in general, has use where a relatively light-weight strong material is desired; where a substantially fireproof, rustproof, rotproof, vermin and rodentproof material is desired without the necessity of painting or coating. The material has greater heat and sound insulation than the unmixed metal comprising the matrix, and can be used Where a floating material is desired and where deterioration is a problem. The material may be used in making castings of light weight, the aggregate being employed as a filler for the more expensive metal. It may also be used as a relatively inexpensive, light-weight core material for fire doors or the like. It can be conveniently handled, since it may be readily sawn and will retain nails or other fastening means.

We claim as our invention:

1. A light-weight solid product having a high strengthto-weight ratio which can be readily sawn comprising a metallic matrix and mineral aggregate in particle form embedded and substantially uniformly dispersed in said matrix, said metal being of the class consisting of aluminum and magnesium and alloys thereof, said aggregate being selected from the group consisting of vermiculite and fired clay pellets and having a melting point above the melting point of the metal and being of relatively light weight and substantially stable in the presence of said metal when the latter is in molten condition, said aggregate being in major proportion by volume and substantially uniformly distributed in discrete pieces throughout said metallic matrix, the latter being in the external continuous phase.

2. The composition of claim 1 wherein the metal is aluminum.

3. The composition of claim 1 wherein the metal is magnesium.

3 4 5. The composition of claim 1 wherein the aggregate 2,763,519 Thomson Sept. 18, 1956 is fired clay pellets. 2,805,473 Handwerk Sept. 10, 1957 2,929,133 Hughes Mar. 22, 1960 References Cited in the file of this patent 2,947,068 Nachtman Aug. 2, 1960 UNITED STATES PATENTS 5 2,951,280 Spokes p 1960 934,412 Marius Sept. 14, 1909 FOREIGN PATENTS 2,568,157 Lepp Feb. 12, 1949 456,467 Canada May 3, 1949

Claims

1. A LIGHT-WEIGHT SOLID PRODUCT HAVING A HIGH STRENGTHTO-WEIGHT RATIO WHICH CAN BE READILY SAWN COMPRISING A METALLIC MATRIX AND MINERAL AGGREGATE IN PARTICLE FORM EMBEDDED AND SUBSTANTIALLY UNIFORMLY DISPERSED IN SAID MATRIX, SAID METAL BEING OF THE CLASS CONSISTING OF ALUMINUM AND MAGANESIUM AND ALLOYS THEREOF, SAID AGGREGATE BEING SELECTED FROM THE GROUP CONSISTING OF VERMICULITE AND FIRED CLAY PELLETS AND HAVING A MELTING POINT ABOVE WEIGHT AND SUBSTANTIALLY STABLE IN THE PRESENCE OF SAID METAL WHEN THE LATTER IS IN MOLTEN CONDITION, SAID AGGREGATE BEING IN MAJOR PROPORTION BY VOLUME AND SUBSTANTIALLY UNIFORMY DISTRBUTED IN DISCREAT PIECES THROUGHTOUT SAID METALLIC MATRIX, THE LATTER BEING IN THE EXTERNAL CONTINUOUS PHASE.