Armor Plate, Armor Plate Composite and Armor

Abstract

An armor plate consists of a material comprising a cermet, and the armor plate has a density in the range from 5.0 to 6.5 g/cm.sup.3. An armor plate composite and an armor are provided as well.

Claims

1. An armor plate consisting of a material comprising a cermet, wherein the armor plate has a density in the range of from 5.0 to 6.5 g/cm.sup.3.

2. The armor plate according to claim 1, wherein the cermet comprises as main component a titanium-based hard material, especially a hard material based on titanium chosen from the group of TiC, TiCN and combinations thereof.

3. The armor plate according to claim 2, wherein the cermet in addition to the titanium-based hard material comprises a further hard material which is chosen from the carbides of tungsten, molybdenum and mixtures thereof.

4. The armor plate according to claim 1, wherein the cermet is free of carbides, nitrides and carbonitrides of tantalum and/or niobium.

5. The armor plate according to claim 1, wherein the cermet comprises a binder, and wherein the binder is composed of the elements chosen from the group of cobalt, nickel, copper, iron and mixtures thereof, preferably chosen from the group of cobalt, nickel and mixtures thereof, particularly preferred wherein the binder is nickel.

6. The armor plate according to claim 1, wherein the armor plate has a compressive strength in the range of from 4400 to 5800 MPa, preferably in the range of from 4600 to 5700 MPa.

7. The armor plate according to claim 1, wherein the armor plate has a Vickers hardness (HV30) in the range of from 1000 to 2000, preferably in the range of from 1300 to 1900.

8. The armor plate according to claim 1, wherein the armor plate has a fracture toughness K.sub.1c in the range of from 6 to 12 MNm.sup.−3/2, preferably in the range of from 6.5 to 10.5 MNm.sup.−3/2.

9. The armor plate according to claim 1, wherein the armor plate has a transverse rupture strength in the range of from 1000 to 2000 MPa, preferably in the range of from 1050 to 1950 MPa.

10. The armor plate according to claim 1, wherein the armor plate has a thickness of 3.0 mm or more, preferably a thickness in the range of from 3.0 to 8.0 mm, particularly preferred of from 3.5 to 7.0 mm.

11. The armor plate according to claim 1, wherein the armor plate has an edge length of 5.0 mm or more, preferably of 10.0 mm or more.

12. The armor plate according to claim 1, wherein an upper side of the armor plate is sandblasted.

13. An armor plate composite, comprising at least two layers of armor plates according to claim 1, which are connected to one another.

14. The armoring according to claim 1, wherein the carrier is the outer side of an object provided with the armoring, in particular a vehicle or a mobile unit.

15. An armor plate consisting of a material, and wherein the material consists of a cermet comprising 60 to 95 weight percent of a titanium-based hard material, up to 30 weight percent of a further hard material, and 1 to 20 weight percent of a binder, based on the total weight of the material, and wherein the armor plate has a density in the range of from 5.0 to 6.5 g/cm.sup.3.

16. An armor plate consisting of a material comprising a cermet, wherein the armor plate has a density in the range of from 5.0 to 6.5 g/cm.sup.3, and wherein the armor plate has a Vickers hardness (HV30) in the range of from 1000 to 2000, wherein the armor plate has a fracture toughness K.sub.1c in the range of from 6 to 12 MNm.sup.−3/2 and wherein the armor plate has a transverse rupture strength in the range of from 1000 to 2000 MPa.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Further features and advantages of the invention result from the following description of exemplary embodiments, from the examples and from the drawings. The figures show:

[0088] FIG. 1 an armor plate according to the invention in a perspective, schematic view;

[0089] FIG. 2 armor according to the invention with a carrier onto which a plurality of armor plates according to FIG. 1 are glued by means of an adhesive layer in cross-section;

[0090] FIGS. 3a to 3c perspective views of various geometries of the armor plate according to FIG. 1;

[0091] FIG. 4 armor according to the invention with a carrier onto which a plurality of armor plate composites according to the invention comprising the armor plate according to FIG. 1 are glued by means of an adhesive layer in cross-section;

[0092] FIG. 5 an alternative embodiment of an armor of FIG. 2 with a fragment protection and an additional protection in cross-section;

[0093] FIG. 6 a cross-section through a further alternative embodiment of the armor of FIG. 2;

[0094] FIG. 7 a cross-section through yet another alternative embodiment of the armor of FIG. 2 with spacers;

[0095] FIG. 8 a schematic cross-section of a test setup for a ballistic test of the armor plate according to FIG. 1;

[0096] FIG. 9 a schematic front view of the test setup of FIG. 8;

[0097] FIG. 10 a schematic cross-section of an alternative test setup fora ballistic test of the armor plate according to FIG. 1; and

[0098] FIGS. 11-18 SEM images of armor plates according to the invention according to FIG. 1.

[0099] The same reference signs are used in all figures for the same parts and components, and the corresponding advantages and characteristics listed in relation to one embodiment apply analogously to the components having the same reference sign in different embodiments.

DETAILED DESCRIPTION

[0100] Structure and Design of Armor Plates, Armor Plate Composites and Armor

[0101] FIG. 1 schematically shows an armor plate 10 according to the invention, which in the shown design example is rectangular and has a constant thickness d.

[0102] The thickness d is several millimeters and depends on the desired protective effect. The armor plate preferably has a thickness greater than 3 mm or more.

[0103] The thickness of the armor plate 10 is always selected such that the plate as such is inherently stable and is destroyed only when under fire.

[0104] The dimensions of the armor plate 10 are comparatively low. The edge lengths a and b are in the order of 10 mm to 150 mm and preferably in the range from 20 to 50 mm. It goes without saying that the exact dimensions for the intended location of use can be selected by the skilled person as required.

[0105] The armor plate 10 is a solid part of a material comprising a cermet, whereby the armor plate 10 has a density in the range from 5.0 to 6.5 g/cm.sup.3.

[0106] The customary sintering processes generally known in the prior art for these materials can be used to produce the armor plate 10.

[0107] FIG. 2 shows the structure of an armor 11 according to the invention comprising a plurality of the armor plates 10 shown in FIG. 1.

[0108] The armor 11 shown in FIG. 2 uses a carrier 12 onto which the armor plates 10 are glued adjacent to one another. The armor plates 10 accordingly form an armor layer 13 of the armor 11.

[0109] In the shown embodiment, the carrier 12 consists of a steel alloy, in particular a high-strength steel alloy as used in the armoring of vehicles, for example armor steel.

[0110] In principle, however, a large number of other materials besides high-strength steel are suitable for the carrier 12, for example aluminum, aluminum alloys, titanium, titanium alloys, synthetic fiber composite materials and/or combinations thereof.

[0111] The armor plates 10 are glued to the carrier 12 by means of a first adhesive layer 14. The adhesive forming the first adhesive layer 14 is a silicone-based adhesive.

[0112] In principle, it is conceivable to use an adhesive layer with a constant thickness, so that a continuous, flat adhesive layer 14 is applied to the carrier 12.

[0113] The embodiment in FIG. 2 shows an alternative form of the adhesive layer 14, in which said adhesive layer has a generally wavy profile when viewed in cross-section. The armor plates 10 are consequently only in contact with the (flattened) wave crests of the first adhesive layer 14. “Channels” 16 are formed between the individual wave crests, each of which is filled with air.

[0114] Such an adhesive layer 14 is more complex to produce, however, so that this embodiment is primarily suitable for the initial production of armor 11. On the other hand, if the armor 11 only needs to be repaired, or if the manufacturing process is to be further simplified, a flat adhesive layer 14 can be used as well.

[0115] The particular advantage of the armor 11 shown in FIG. 2 is that the individual armor plates 10 can easily be replaced separately should this be necessary. The first adhesive layer 14 ensures mechanical damping between the armor plates 10 and the underlying carrier 12, which increases the protective effect.

[0116] In deviation from the rectangular shape of the armor plates 10, in principle any shape can be used that is suitable for completely covering an underlying surface (apart from joints between the adjacent armor plates 10) with a plurality of adjacently disposed armor plates. Therefore, different geometries of the armor plates 10 are shown in FIGS. 3a to 3c. For example, the armor plates 10 can be square or rectangular (FIG. 1 and FIG. 3a), triangular (FIG. 3b), or hexagonal (FIG. 3c).

[0117] The joints between adjacent armor plates 10 should have a width in the range from 0.01 to a maximum of 0.08 mm so as to ensure a sufficiently good protective effect of the armor 11. If necessary, the individual armor plates 10 can be ground to the desired size after the manufacturing process in order to eliminate manufacturing-related tolerances and ensure sufficiently small joints.

[0118] FIG. 4 shows a further embodiment of the armor 11, which comprises an armor plate composite 18 that forms the armor layer 13.

[0119] The armor plate composite 18 is glued to the carrier 12 by means of the first adhesive layer 14. The first adhesive layer 14 is implemented with a constant thickness.

[0120] The armor plate composite 18 comprises a plurality of layers 20a and 20b, which are connected to one another by means of a second adhesive layer 22 (“sandwich construction”). In this case, the whole armor plate composite 18 forms the armor layer 13 of the armor 11 a.

[0121] Each of the layers 20a and 20b comprises a plurality of armor plates 10a and 10b, whereby the material of which the armor plates 10a and 10b are made can differ between the layers 20a and 20b.

[0122] The armor plates 10a and 10b can comprise or consist of cermets having different compositions, for example.

[0123] The armor plates can furthermore also differ within one or each of the layers 20a and 20b, so that different armor plates 10a and 10a′ or 10b and 10b′ are used, for example.

[0124] An optimal compromise between the protective effect, the cost and the weight of the armor 11 can thus be made via the selection of the materials of the armor plates 10a and 10b.

[0125] In this embodiment, there are overall two layers 20a and 20b made of armor plates 10a and 10b. Even so, the armor plate composite 18 can also consist of more than two layers. It is, however, advantageous to use as few layers as possible to achieve the desired protective effect, and in particular only one layer as shown in FIG. 1, in order to keep the weight of the armor 11 as low as possible.

[0126] The possible maximum usable overall weight of the armor 11 is usually determined by the object that is to be provided with the armor 11.

[0127] Compared to the embodiment shown in FIG. 2, the individual armor plates 10a and 10b can have a smaller thickness, so that the armor plate composite 18 overall has a thickness analogous to the thickness of the armor layer 13 of FIG. 1.

[0128] The first adhesive layer 14 and the second adhesive layer 22 can use the same or different adhesives. The second adhesive layer can also have “channels” 16 like the first adhesive layer 14, or a constant thickness as shown in FIG. 4. The second adhesive layer 22 ensures mechanical damping between the armor plates 10a and 10b or 10a′ and 10b′.

[0129] As is the case with the first adhesive layer 14, the layers 20a and 20b can also be connected to one another by means of sintering, screwing or soldering, in particular hard soldering, instead of via the second adhesive layer 22.

[0130] In the embodiment shown in FIG. 4, the layers 20a and 20b of the armor plate composite 18 are arranged one above the other such that, viewed in cross-section, the armor plates 10a and 10b of layers 20a and 20b are arranged one above the other, so that the armor plates 10a and 10b lie congruently one above the other, thus also positioning the joints between the armor plates 10a and 10b one above the other. If the joint width is sufficiently small, it has been shown that no impairment of the protective effect of the armor 11 is to be expected in this case either. With such an arrangement, it is particularly easy to replace individual armor plates 10a and 10b as well as entire armor plate composites 18, for example after damage to the armor 11a.

[0131] The armor plates 10a and 10b can alternatively also be arranged offset to one another, so that the joints between the individual armor plates 10a and 10b are not positioned exactly one above the other. Even if the protective effect of the armor 11 can theoretically be further increased in this way, in particular with respect to the event of repeated ballistic impact at the same location of the armor 11, the cost of a repair increases in such an embodiment.

[0132] Consequently, there has to be a trade-off between manufacturing costs, stability of the armor and the effort in the event of a repair.

[0133] FIG. 5 shows a further embodiment of the armor 11, in which a fragment protection 24 is applied, in particular glued, to the side of the armor layer 13 opposite to the adhesive layer 14.

[0134] The armor layer 13 can be constructed of individual armor plates 10 or of armor plate composites 18 as in the embodiments shown above.

[0135] The fragment protection 24 is, for example, made of steel, high-strength steel, titanium, titanium alloys, aluminum, aluminum alloys, composite materials in particular carbon- and/or plastic-based, and/or combinations thereof.

[0136] The fragment protection 24 generally has a smaller thickness than the armor layer 13.

[0137] If a projectile hits the armor 11, for example, the armor plates 10 of the armor layer 13 can fragment as a result of the impact. The fragment protection 24 ensures that these fragments cannot spall off the surface of the armor 11b to any significant degree. It has been shown that this can further increase the stability of the armor layer 13 as a whole and thus the protective effect of the armor 11.

[0138] The armor 11 shown in FIG. 5 further comprises an additional protection 26 on the side of the carrier 12 opposite to the adhesive layer 14. The additional protection 26 is in particular glued and/or mechanically fastened to the carrier 12.

[0139] In particular foils and/or mats made of in particular carbon- and/or plastic-based composite materials can be used as the additional protection.

[0140] The additional protection 26 serves to absorb smaller fragments of the carrier 12 and/or the projectile that can occur when the armor is under fire.

[0141] FIG. 6 shows a further embodiment of the armor 11, which comprises the fragment protection 24 and the additional protection 26 analogous to FIG. 5. In the embodiment shown in FIG. 6, however, the carrier 12 is the outer side 28 of an object provided with the armor 11, so that part of the object itself is also part of the armor 11.

[0142] The object is a vehicle or a mobile unit, for example. Mobile unit here refers in particular to temporary infrastructure, for example a container.

[0143] An already existing protective effect of the object, for example the armored outer layer of a vehicle, can thus be exploited and its protective effect merely supplemented by the additional components of the armor 11. A retrofitting of already existing objects with the armor 11 is thus easily possible as well.

[0144] The additional protection 26 is in particular advantageous in an embodiment according to FIG. 6, for example when an occupant of an armored vehicle is positioned directly behind the carrier 12. Even if the projectile that hits the armor 11 when it is under fire, for example, cannot penetrate said armor, fragments could spall off the carrier 12 in the direction of the occupant and injure him. This is effectively prevented by the additional protection 26.

[0145] Since the armor layer 13 and the carrier 12 absorb most of the force of the impact, the parts of the carrier 12 that spall off in the direction of the occupant hardly have any penetrating power, so that a thin foil and/or mat is sufficient as the additional protection 26.

[0146] FIG. 7 shows yet another embodiment of the armor 11, wherein the armor 11 is fastened to the outer side 28 of an object with the aid of spacers 30, in particular on the outer side of a vehicle or a mobile unit.

[0147] Such an embodiment is suitable in particular when the carrier 12, the armor layer 13 and/or the adhesive layer 14 cannot be mounted directly on the outer side 28 or the outer side 28 itself is not made of a sufficiently stable material, so that an embodiment according to FIG. 6 cannot be realized.

[0148] The spacers 30 additionally ensure that fragments or spellings of the carrier 12, for example, do not strike the outer side 28 directly when the armor 11 is under fire. Accordingly, no additional protection 26 is provided in the embodiment according to FIG. 7.

[0149] The spacers 30 also make it easy to replace the armor 11 in the event of damage, because the armor only has to be detached from the spacers 30 and new armor 11 mounted at the damaged location.

[0150] Ballistic Tests 1

[0151] Table 1 shows compositions of armor plates tested as examples and Table 2 shows their physical and mechanical properties.

TABLE-US-00001 TABLE 1 Compositions of the material of the armor plates; all content information is based on the overall weight of the material. Specimen TiC TiCN WC Mo.sub.2C Co Ni Fe A 71.00 — — 9.00 — 20.00 — B 77.50 — — 9.00 — 13.50 — C 81.00 — — 9.00 — 10.00 — D 85.00 — — 9.00 — 6.00 — E: 88.00 — — 9.00 — 3.00 — F 33.50 33.50 11.00 9.50 8.30 4.20 — G 81.00 — — 9.00 — 7.50 2.50

TABLE-US-00002 TABLE 2 Properties of the armor plates Com- Vickers Fracture Transverse Density pressive hard- toughness rupture in strength ness K.sub.1c in strength Specimen g/cm.sup.3 in MPa HV30 MNm.sup.−3/2 in MPa A 5.80 n.d. 1380 10.4 1650 B 5.60 n.d. 1570 8.4 1700 C 5.50 n.d. 1680 8.0 1600 D 5.40 n.d. 1770 7.0 1350 E 5.30 4680 1850 6.7 1100 F 6.10 5640 1690 8.5 1900 G 5.50 n.d. 1680 7.1 1380  H* 3.15 3500 2200- 3.2 400 (SiC) 2500 n.d.: not determined *Literature references

[0152] From Tables 1 and 2 it can be seen that the density can be reduced, the hardness can be increased, the fracture toughness can be lowered and the transverse rupture strength can be decreased by increasing the proportion of titanium-based hard material. A tailored characteristic profile of the armor plate according to the invention can thus be achieved via the selection of the proportions of titanium-based hard material.

[0153] FIGS. 8 and 9 schematically show a cross-section of a first test setup for testing the behavior of the armor plates according to the invention under fire.

[0154] In the first test setup, the respective armor plate 10 to be tested was fastened to a carrier by means of a 3 mm thick adhesive layer and an 8.5 mm thick plate of armor steel Armox® 500T was used as the carrier.

[0155] Support plates 32 were mounted on the carrier peripherally adjacent to the armor plate 10 to be tested. Armor plates of the same size as the armor plate 10 to be tested were used as the support plates 32.

[0156] Plates having the following composition were used as support plates 32: 63 weight percent TiCN, a total of 25 weight percent of WC, Mo.sub.2C, TaC and NbC, as well as 8 weight percent Co and 4 weight percent Nickel. The support plates had a density of 6.45 g/cm.sup.3 and a Vickers hardness (HV30) of 1650.

[0157] The tested armor plates had an edge length of 22.8 mm.

[0158] The center of the armor plate 10 to be tested was fired upon with a 7.62×51 AP8 caliber cartridge with a target velocity of 930 m/s.

[0159] In FIG. 8, the direction of fire is indicated by the arrow B and, in FIG. 9, the location of impact is indicated by the cross K.

[0160] Table 3 shows the results of the ballistic tests for different thicknesses of the armor plates.

TABLE-US-00003 TABLE 3 Results of the ballistic tests 1. Plate thickness in mm Specimen 4.0 5.0 5.7 6 7 C n.d. Penetration Penetration Stopped Stopped E n.d. Penetration Stopped Stopped Stopped F Penetration Stopped n.d. Stopped Stopped G n.d. Penetration n.d. Stopped Stopped n.d.: not determined

[0161] Table 3 shows that all of the tested compositions are suitable as material for armor plates. It can be seen that higher density plates tend to allow for thinner armor plates that withstand ballistic impact. It follows that, in the case of lower density armor plates, the resulting overall weight can still be kept comparatively constant.

[0162] Ballistic Tests 2

[0163] FIG. 10 schematically shows a cross-section of an alternative test setup for testing the behavior of the armor plates according to the invention under fire.

[0164] In the alternative test setup, the armor plate 10 to be tested was mounted on a carrier 12 via spacers 30 as a composite system consisting of fragment protection, armor plate, adhesive layer and additional protection, also referred to as “baking”, whereby an air gap having a thickness of 15 mm was created between the composite system and the carrier.

[0165] An 8.5 mm thick plate made of 500 HB armored steel was used as the carrier.

[0166] Table 4 shows the results of the ballistic tests according to STANAG 4569. In the case of multiple impact ballistic tests, the stated target velocities refer to the target velocities of the successive rounds of firing.

TABLE-US-00004 TABLE 4 Results of the ballistic tests 2 Type Target speed Specimen Specimen Cartridge of fire in m/s E F 7.62 × 51 Repeated fire E: 931, 937, 927, Stopped Stopped AP 922; F: 928, 922, 923, 928 Single fire E: 982; F: 993 Stopped Stopped E: 873; F: 866 Stopped Stopped E: 826; F: 810 Stopped Stopped 7.62× Single fire E: 867, 861, 855, Stopped Stopped 54R B32 851; API F: 859, 852, 857, Dragunov 862 FSP20 Single fire F: 799 n.d. Stopped F: 820 n.d. Stopped F: 851 Stopped F: 900 Stopped E: 971; F:964 Stopped Stopped E: 1008; F: 1012 Stopped Stopped n.d.: not determined

[0167] Specimens E and F had the same compositions as discussed above for the ballistic tests 1.

[0168] The armor plates of Specimen E were tested at a thickness of 5.2 mm and the armor plates of Specimen F were tested at a thickness of 5.9 mm.

[0169] The tested armor plates had an edge length of 11.5 mm and a hexagonal shape.

[0170] From Table 4, it can be seen that the armor plates according to the invention reliably stop the projectile in the case of a single ballistic impact and also in the case of multiple ballistic impacts according to STANAG 4569.

[0171] Surface Treatment

[0172] Armor plates having the compositions according to Specimens E and F were additionally examined using scanning electron microscopy (SEM).

[0173] FIG. 11 and FIG. 13 show a surface photo and a sectional image onto or through an armor plate according to Specimen E. In particular in FIG. 13, it can be clearly seen that the binder accumulates on the upper side of the armor plate (bright regions in the SEM image), as a result of which a binder-depleted zone forms below this region.

[0174] This effect is attributed to diffusion effects during sintering of the armor plate and results in a gradient structure of the armor plate across its thickness, which can reduce the robustness of the armor plate.

[0175] Therefore, to further increase the robustness of the armor plate, the upper side of the armor plate can be sandblasted. FIGS. 12 and 14 show a surface photo and a sectional image onto or through an armor plate according to Specimen E after sandblasting.

[0176] Sandblasting was carried out using a continuous belt blasting machine of the company Rosier RSKI 1400. Four blast nozzles and a blasting pressure of 6 bar were used. The distance to the workpiece was 20 cm and the feed rate during sandblasting was 0.2 m/min with a total blasting time of one minute.

[0177] “WR—aluminum oxide brown” of the company Werner Rumler Industriebedarf & Strahlmittel GmbH of the category Fepa 80 with a grain size in the range from 149 to 210 μm was used as the blasting medium.

[0178] FIG. 12 shows that sandblasting results in a more even surface structure, the roughness of which can be adjusted via the selected sandblasting process.

[0179] From the sectional view in FIG. 14, it can be seen that the metallic binder-enriched zone on the upper side of the armor plate has been removed.

[0180] FIGS. 15 to 18 show analogous images for armor plates according to Specimen F, whereby FIGS. 15 and 17 respectively show a surface view and a sectional view before sandblasting, and FIGS. 16 and 18 respectively show a surface view and a sectional view after sandblasting.