DE1758669A1 - Manufacturing process for mixed composite materials - Google Patents

Description

Dipl .- 'ng. Dip ¹ ■: Sl

DicT.rCi: .- .. '^! CY' June 25, 1968

PATENTAi ¹ V- vT
Müüdcc Π - Orucrdstr. 81 1758669 "

Telephone 5617 62

Compagnie Fran ^ aise Thomson Houston - Hotchkiss Brandt, Paris 8e "ne, Boulevard Faussmann 173 (France)

_n Manufacturing process for mixed composite materials "

French priority dated June 23, 1967 from French patent application lir. 112 162 (Seine)

The invention relates to manufacturing methods for composite materials and, in particular, for mixed composite materials. With these materials a lethal code becomes Flastik ilatrize reinforced at the same time by long threads and short fibers. The invention is equally concerned with the mixed composite materials produced by these processes as well as those made from these memory materials manufactured products or devices.

Two main groups of composite materials are currently known, consisting of a metal or plastic ilatrize be formed into the

- either short fragile fibers:?. Material with high mechanical properties, high modulus of elasticity and high breaking strength - so in particular thread-like crystallites of refractory mixtures with covalent bonding, i.e. boriue, nitride, carbide and Oxides, -

or long, continuous threads are poured in, the latter having lower mechanical properties, in addition, however, allow a weight saving due to their low density. Examples are here Threads made of Siliciumdioxycl, 5or, Siliziuuu-iarbic, Carbon called.

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These two groups of composite materials on the one hand offer a high reinforcing effect, but have compared to their continuity along a piece, have strongly different mechanical values. The mechanical Properties of the composite materials formed with the aid of short fibers are in any case below those of materials formed with the help of long threads. The load transfer between the die and the fiber only takes place in optimal shape when the ratio between the length and diameter of the fiber exceeds a critical value, the in turn, it depends on the weight limit of the fiber and the quality of the internal connection between the fiber and the die depends.

The properties of a composite material determined during a fracture test also differ in both cases. One made of long fibers Composite material is significantly more sensitive to notch loading than a composite material formed from short fibers, due to the fact that the cracks occurring in the thread structure spread almost instantaneously be able to spread a piece once the cracks have reached a critical level. If, on the other hand, reinforcement is carried out with the aid of short fibers, the size of the cracks occurring during a fracture can be critical below this Worth being held. In contrast to a fully koaoenan and sudden collapse, there is only one break local and delayed breakage of the respective part.

Subject of the invention.1st the creation of mixed composite materials, which are formed from long threads and short fibers melted into a die and at the same time have the following properties!

high breaking strength, high modulus of elasticity, low notch sensitivity and the ability to retard breakage.

The attached drawing schematically explains the structure of a mixed composite material produced according to the invention.

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The threads 1 have the length of the respective workpiece or a large part in the order of magnitude of about a meter. The one along the maximum load direction The threads 1 arranged on the workpiece mainly ensure the mechanical strength under external stress. The long threads 1, which are fragile but have high mechanical properties, form in each If there is a high proportion of voluro inside the die.

The short fibers 2 are each located between the long threads 1, but without being in direct contact with them, whereby damage to the long threads 1 is avoided. The length of these short fibers 2 is usually one Millimeter. The fibers 2, which are located in the die with a low volume fraction, have their task primarily in to inhibit or prevent cracking and macroscopic defects in the composite material.

The die 3 consists of a stretchable or pseudo stretchable material and offers good cohesion between the long threads 1 and the short fibers 2. This die 3 is used primarily to ensure a good load distribution.

It is assumed here that each element made of composite material can be used within a structure which can reduce the pronounced anisotropic character of the workpieces, this character being related to the orientation of the long threads 1. By superimposing panels, the reinforcing fibers of which are each aligned with a distance of 120 ° from each other, is achieved an isotropic structure that can withstand any load parallel to dftn panels.

According to the invention there is a mixed composite material of long threads 1 and short fibers 2, melted in a die, in particular according to the method mentioned below or variants manufactured «

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a) A mixture of molten metal and short fibers 1 is poured onto an array of long threads 1 previously aligned in a mold. To avoid any damage to the long threads 1 when they come into contact with the short threads. In addition, the long threads 1 are optionally covered with a fine metal layer with a rapid passage through a Melt bath, coated by electrolytic deposition, evaporation in a vacuum or by decomposition in the vapor phase.

b) Within a variant of the aforementioned method the die used is made of plastic resin

c) The long threads 1 passing through are coated with a fine metal layer containing fibers, namely when passing through a molten bath containing these fibers or when Passage through an electrolytic bath enriched with conductor fibers. After arrangement and alignment in one The metal matrix is introduced in the molten state by electrolysis or sintering.

d) The long threads 1 passing through are "coated with a sticky layer, with the aid of which fibers during the subsequent passage through a solution containing these fibers be included. The long threads 1 coated on these catfish are aligned in a mold and the adhesive layer removed by heating in a vacuum · The metal matrix is introduced in the molten state by sintering

·) In a variant · of the aforementioned procedure the matrix used · made of plastic resin. The matrix is introduced here in two separate stages here the adhesive layer is applied and the fibers are bound by the resin, on the other hand the resin is incorporated into the structure or the Skeleton of the aligned long threads 1 introduced

f) A skeleton of aligned long threads 1 is made with an easily distillable solution filled with fibers · After the solvent has been distilled, the grouping of long threads 1 and short fibers 2 is * the molten bath or electrolytic way in a metal matrix and infiltrated in a plastic matrix

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g) By circulation of an enriched with conductor fibers Electrolysis bath through a skeleton of aligned long threads 1 creates a structure through fiber and metal coating on the long threads 1. This structure or this skeleton will later be infiltrated in a molten metal bath or filled by sintering.

According to the invention, it is also possible to make a mixed composite material by providing short Fibers or filiform crystals within a Produce thread structure. With one with the help of long A fiber structure is created in a fiber-reinforced material in place by unidirectional solidification of an alloy ^ which the formation of an intermediate layer in the form of thread-like crystals.

For this purpose, one chooses, for example, an Al - Ni alloy with a high volume fraction of long threads made of silicon carbide. The transformation of the matrix from the liquid to the solid state by slowly passing through a temperature gradient produces the growth of an aligned structure of thread-like crystallites or elongated Ilonocrystals of the mixture Al ₃ Ni in the AL-Nl matrix and between the fibers.

It goes without saying that the exemplary given description includes all possible variants equally in the invention.

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Claims (1)

Compagnie Prancaise Thomson Houston - Hotchklss Brandt, Paris 8ferae, Boulevard Haussmann 173 (France) Claims t Manufacturing process for mixed composite materials with long threads and short fibers, characterized in that a mixture of molten metal and short fibers (2) contained therein is poured onto a grouping of long threads (1) in a prepared mold, whereby to avoid damage to the long threads (1) by the short fibers (2) these long threads are coated with a fine metal skin and this coating is applied either by rapid passage into a molten bath, by electrolytic deposition, by evaporation in a vacuum or by decomposition in the vapor phase will. Method according to Claim 1, characterized in that the die (3) used consists of plastic resin. Manufacturing process for mixed composite materials with long threads (1) and short fibers (2), characterized in that the long continuous threads (1) of a fine, fiber-containing metal layer are surrounded, this coating either by passage in a molten bath containing these fibers or by passage through an electrolytic bath containing conductor fibers and the metal matrix after Insertion and alignment in a fora int liquid state is melted down by electrolysis or sintering. Manufacturing process for mixed composite materials with long threads (1) and short fibers (2), characterized in that the threads (1) passing through are of a sticky type The rails are surrounded by which the fibers (2) are subsequently passed through a solution containing these fibers 4286 - 2 - 008886/0724 BATH take-up, and these threads (1) aligned in a Torn are then passed through the sticky layer Heating iir. Vacuum. is removed and the! letal Lv.atri ze iir. reschr.olzcr.on Custanc 'added by sintering' ./ird. Method according to claim 4, characterized in that dai. the die (3) used is made of plastic resin. Manufacturing process for mixed composite materials with long threads (1) and short fibers (2), characterized in that a skeleton of long threads (1) is filled with an easily distillable solution of fibers (2), the Solvent the grouping of long threads (1) and short fibers (2) a: ictall.T.atrize in the Sc>. < UUzbad, on electrolyte! See Vegc or a riastiknatrize by infiltration is given. Manufacturing process for mixed composite materials with long threads (1) and short fibers (2), characterized in that a skeleton by means of fiber and rivet support on the long threads (1) is created by circulating an electrolysis bath containing conductor fibers through an aligned structure of long threads (1) ) arises un ■ '. this skeleton is then filled in by infiltration in a metal bath or by sintering. Manufacturing process for mixed composite materials with long threads (1) and short fibers (2), characterized in that that the mixed composite material by local generation of a taser structure via unidirectional solidification an alloy is created. Mixed composites or products or devices these substances, characterized in that they are described according to one of the claims 1, 3, 4, 6, 7 or 8 Process are produced. 009886/0724 M Letter »