Reinforced metal alloy for enhanced armor protection and methods
11243052 · 2022-02-08
Assignee
Inventors
Cpc classification
F41H5/0464
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F41H5/0414
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
B29C70/86
PERFORMING OPERATIONS; TRANSPORTING
B29C70/56
PERFORMING OPERATIONS; TRANSPORTING
B29C70/543
PERFORMING OPERATIONS; TRANSPORTING
B22D19/02
PERFORMING OPERATIONS; TRANSPORTING
International classification
F41H5/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
B22D19/02
PERFORMING OPERATIONS; TRANSPORTING
Abstract
An armor plate and method of making an armor plate is provided having the steps of: suspending a carbon fiber weave within a mold; heating aluminum 6061 or 7075 alloy to a molten state; pouring the molten aluminum into the mold having ceramic particulates in the range of 1 to 60 percent by volume of the molten aluminum and in the range of 3-44 microns in diameter; cooling the resultant matrixed aluminum to ambient temperature; and laminating at least two layers of ballistic fiber to the matrixed aluminum.
Claims
1. A method of making an armor plate comprising the steps of: suspending a carbon fiber weave within a mold; heating aluminum 6061 or 7075 alloy to a molten state; pouring the molten aluminum into the mold having ceramic particulates in the range of 1 to 60 percent by volume of the molten aluminum and in the range of 3-44 microns in diameter; cooling the resultant matrixed aluminum to ambient temperature; and laminating at least two layers of ballistic fiber to the matrixed aluminum.
2. The method of claim 1, wherein the aluminum is heated to about 1,400 degrees Fahrenheit.
3. The method of claim 1, the ceramic particulate is in the range of 40 to 50 percent by volume of the cast aluminum alloy and in the range of 6-20 microns in diameter.
4. The method of claim 1, wherein the step of suspending the carbon fiber weave within a mold uses caplets.
5. The method of claim 1, further comprising the step of spraying the armor plate with a blast mitigation and protective coat.
6. The method of claim 1, wherein the ceramic particulate is at least one of silicon carbide and boron carbide.
7. The method of claim 1, wherein ceramic particulate is dry mixed with aluminum alloy powder in a rotary batch or V mixer prior to heating and casting of aluminum alloy.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The foregoing features, as well as other features, will become apparent with reference to the description and figures below, in which like numerals represent like elements, and in which:
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(24) While the features described herein may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to be limiting to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims.
DETAILED DESCRIPTION
(25) With the ever changing military and law enforcement theatres, evolving needs for improved armor protection for both personnel and vehicle systems have increased to meet lighter weight and higher performance expectations. The exemplary metal alloys and methods described herein and depicted in the figures are configured to meet these increased expectations.
(26) The present embodiments include methods to produce a reinforcement lamination for a metal alloy to be used for ballistic resistant armor applications such as personnel or vehicular armor plates. In one embodiment the base metal is configured with mesh reinforcement (e.g., carbon fiber or basalt) within the layer (including a cast layer) to provide enhanced strength and energy absorption characteristics.
(27) According to one approach, through innovative nanostructured alloy assembly development, some embodiments can enhance the material performance characteristics of the base metal for use in defense armor applications. Although the present embodiments and assembly principles are described for armor applications, it is noted that these embodiments and methods may also be applied to industrial, structural applications, and the like where improved strength to weight ratios are of critical importance.
(28) One aspect of the invention includes a process for embedding a reinforcement fiber mesh such as, but not limited to, carbon fiber or basalt fiber within a cast metal alloy, such as but not limited to, aluminum 6061 or 7075 alloy. Other base metals may be used for enhanced performance characteristics. Within this embodiment, the mesh may be suspended within the mold prior to casting and held in place during casting with metal standoffs or nibs or caplets or other types of spacers to help to maintain the position of the reinforcement to ensure coverage at both sides of the reinforcing material. Following the casting process, the plate is allowed to cool and removed from the mold. In one embodiment, the plates can be prepared with a finish edge treatment such as weld and then wrapped with an aramid fiber or ballistic composites wrap such as a ballistic wrap sold under the tradename SPECTRA/SPECTRA GOLD (by Honeywell of Colonial Heights, Va.), or DYNEEMA (by Royal DSM of the Netherlands). In a preferred embodiment, the finish edge can be infused with a resin. Depending on the targeted threat level, a layered backup system may be incorporated in some embodiments having of a series of ballistic fabric materials such as a ballistic foam or an aramid fiber sold under the tradename KEVLAR (by DuPont) or any various types of ultra-high-molecular-weight polyethylene (UHMWP) polymers.
(29) The present embodiments provide several advantages over the known art. One key advantage is the comparative lightweight nature of the product with enhanced strength-to-weight performance of the assembly. This factor will allow military, police and security personnel to wear the protective gear for longer periods of time without additional strain of carrying added weight. Another advantage is its ability to potentially withstand multiple ballistic rounds. This innovation will allow soldiers, police or other security forces to remain engaged in conflict without the immediate need to take cover, retreat, or otherwise disengage in order to replace the damaged gear. And yet another advantage is its ability to absorb ballistic rounds received at an angle (its “obliquity”) (e.g., 0 to about 20 degrees from perpendicular) rather than ricocheting the bullet to potentially cause additional harm once deflected. For example, ceramic based armor plates can frequently deflect bullets into the wearer's arm, torso or neck, or into a fellow soldier in an adjacent position. Capturing a bullet round enhances the safety of those seeking protection. The composite nature of the reinforced metal further improves flexibility, strength and resistance to deformity and failure.
(30) The present embodiments involve matrixed aluminum configured, for example, to be utilized in conjunction with product applications to meet various military and law enforcement expectations for lighter weight and highly capable body armor. It is known that matrixed aluminum, by itself, cannot meet the performance criteria for the higher threat level applications. However, the present embodiments' added layers which synergistically interact together to reinforce the design, define and refine the layup applications to result in a final process and product. Materials needed according to one approach can include a matrixed aluminum plate—6″×6″×⅜″ (″=inches), SPECTRA Cloth, KEVLAR, a blast mitigation and protective spray on (or dipped) coating such as a RHINO COATING (by Rhino Linings Industrial), and optionally labels to indicate strike face and ratings.
(31) According to another approach, a wearable-enhanced-protective-system (WEPS) can be a laminated series of layers functioning homogeneously to mitigate Level 3A ballistic threats. These can include 9 mm FMJ, 0.357 SIG/FMJ and 44 MAG/SJHP as well as the 5.52 FMJ Rifle Round shot at 49 feet from an AR15 Assault Rifle. This gives the System a Level 3A+ Rating based on National Institute of Justice (NIJ) Criteria. The WEPS system of the current embodiments can be a series of laminations and coatings. According to one approach, the system can have a titanium strike face that is the initial surface contact a round would encounter to significantly degrade the level 3A rounds so that the subsequent layers can further degrade and capture the round with limited backface deformation and no penetration.
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(36) According to another approach shown in
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(40) The plate 600″ of
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(42) Another exemplary assembly approach to produce the matrixed aluminum plate 522 is shown in
(43) According to another approach, the present embodiments can utilize a proprietary sequenced manufacturing distribution process of materials and layers under controlled environmental conditions to ensure a consistent, reliable, and reproducible end product. Sheet metal rolling techniques can be employed and tested, including hot/cold rolling, stamping, perforating, and/or casting. Composite matrix materials can be evaluated to determine applicability for bonding, strength, and production benefits. Advanced fabrication techniques such as computer numerical control (CNC) milling, laser/water jet, and/or rapid prototyping can be utilized.
(44) Performance criteria of a resultant composite base metal can be enhanced, and verified through rigorous testing and certification processes. Standard metrics such as, shear, tensile strength, and heat dissipation, can be measured and compared to create products that outperform current National Institute of Justice (NIJ) target threat level specifications. Other industry applications can be reviewed to determine potential candidates for future modification and enhancement. The targeted base metal material has several potential industry applications, including personal body armor and vehicle armor applications, structural and building component applications, marine applications, and electrical and electronic conductive applications. Following the initial proof-of-concept phase, prototype results can be used to determine suitability for various applications. Such as shown in the following table:
(45) TABLE-US-00001 TABLE SYSTEM ASSEMBLY - LAYER THICKNESS THICKNESS (IN) (IN) DIMS WT (LBS) DIMS 1 System Assembly #1 - Threat Level IIIA (plus) WRAP 1 Spectra Shield SR-1226 - Inner Wrap 0.0625 1/10 12″ × 12″ 10.5″ × 11.5″ Matrixed Aluminum 0.2750 3/8 12″ × 12″ 10.5″ × 11.5″ WRAP 2 Spectra Shield SR-1226 - Inner Wrap 0.0625 1/16 12″ × 12″ 10.5″ × 11.5″ Kevlar sheets (8) 1 0.0090 8/889 12″ × 12″ 0.0972 10.5″ × 11.5″ 7 0.0630 8/127 12″ × 12″ 0.6804 10.5″ × 11.5″ WRAP 3 Kevlar sheets (3) - Outer Wrap 00525 1/16 12″ × 12″ 10.5″ × 11.5″ Rhino Spray Coating 0.0625 1/16 12″ × 12″ 10.5″ × 11.5″ TOTALS: 0.6970 0.6970 0.0000 0.7776 0.6521 2 System Assembly #2 - Threat Level IIIA (plus) WRAP 1 Spectra Shield SR-1226 - Inner Wrap 0.0625 1/16 12″ × 12″ Titanium sheet - Grade 5 0.0280 7/250 12″ × 12″ 0.6572 Matrixed Aluminum 0.3750 3/8 12″ × 12″ WRAP 2 Spectra Shield SR-1226 - Inner Wrap 0.0625 1/16 12″ × 12″ Kevlar sheets (8) 1 0.0090 8/889 12″ × 12″ 0.0972 7 0.0630 8/127 12″ × 12″ 0.6804 WRAP 3 Kevlar sheets (3) - Outer Wrap 0.0625 1/16 12″ × 12″ Rhino Spray Coating 0.0625 1/16 12″ × 12″ TOTALS: 0.7250 0.7250 0.0000 1.4348 3 System Assembly #3 - Threat Level IIIA (plus) WRAP 1 Spectra Shield SR-1226 - Inner Wrap 0.0625 1/16 12″ × 12″ Stainless Steel - 18 gauge - Type 304 0.0480 6/125 12″ × 12″ 2.0160 or 316 Matrixed Aluminum 0.3750 3/8 12″ × 12″ 5.238 WRAP 2 Spectra Shield SR-1226 - Inner Wrap 0.0625 1/16 12″ × 12″ Kevlar sheets (8) 1 0.0090 8/889 12″ × 12″ 0.0972 7 0.0630 8/127 12″ × 12″ 0.6804 WRAP 3 Kevlar sheet (3) - Outer Wrap 0.0625 1/16 12″ × 12″ Rhino Spray Coating 0.0625 1/16 12″ × 12″ TOTALS: 0.7450 0.74500 0.00000 8.03160 4 System Assembly #4 - Threat Level IIIA (plus) WRAP 1 Spectra Shield SR-1226 - Inner Wrap 0.0625 1/16 12″ × 12″ Stainless Steel - 18 gauge - Type 304 0.0480 6/125 12″ × 12″ 2.0160 or 316 Matrixed Aluminum 0.3750 3/8 12″ × 12″ WRAP 2 Spectra Shield SR-1226 - Inner Wrap 0.0625 1/16 12″ × 12″ Kevlar sheets (8) 1 0.0090 8/889 12″ × 12″ 0.0972 7 0.0630 8/127 12″ × 12″ 0.6804 WRAP 3 Kevlar sheets (3) - Outer Wrap 0.0625 1/16 12″ × 12″ Rhino Spray Coating 0.0625 1/16 12″ × 12″ TOTALS: 0.7450 0.74500 0.00000 2.79360
(46) Aluminum treatments can also be considered for the present embodiments. Treatments of ferrous and nonferrous castings can receive different types of heat treatment. Aluminum castings can be heat treated using different combinations of operations, called tempers. Heat treatment of aluminum castings can result in homogenization, stress relief, and improved stability, machinability and mechanical properties.
(47) The thermal processing can involve three basic processes—solution, quenching and aging. During solution, elements that will later cause age hardening are dissolved, undissolved constituents become spheroids, and the microstructure of the casting is homogenized. Homogenization distributes the alloying and impurity elements of a casting throughout its matrix, so the casting's properties will be more uniform.
(48) Rapid cooling, or quenching cycles, retain the dissolved elements in the solution. Rapid quenching increases the response to age hardening, but it also creates residual stresses and distortion. Dissolved elements that are trapped in the solution during quenching eventually precipitate slowly at room temperature. After a time at room temperature, some alloys will harden appreciably. Aging can be accelerated by heating castings to intermediate temperatures in a process called artificial aging. Increased time at age temperature or aging at a greater temperature further evolves the precipitate structure, and hardness increases to a peak hardness condition. After the peak is hit, further aging, or overaging, reduces the hardness.
(49) Aging also affects ductility. During overaging, a loss of hardening mechanisms permits extensive deformation to occur before fracture and ductility increases. Annealing, which is extreme overaging, maximizes ductility. Although each alloy and temper can have a recommended solution, quench and age times, these cycles are often customized to meet specific requirements for strength and ductility.
(50) In another approach, additional titanium to the strike face to help degrade the rounds on the strike face gives the layered wraps more stopping opportunity. In one embodiment, a test fired AR15-5.56 FMJ round resulted with no penetration and limited BFD. This was with 0001 which did have a 12 gauge Titanium Layer on the strike-face as well. One embodiment utilized just a Layup and Matrixed Aluminum assembly with the 0.125 Titanium as the Strikeface and defeated the AR15/5.56 FMJ Round as well.
(51) An AK47/7.62 round could be defeated with an embodiment having a 1.25 Strikeface/Matrixed Aluminum/.125 Titanium/Spectra-Kevlar Layup. This could work for Level 3. However, significantly increased weight and cost would result. Optional embodiments could incorporate a Ballistic Foam to go before the matrixed aluminum.
(52) Any references to the advantages, benefits, unexpected results, or operability of the present invention are not intended as an affirmation that the invention has been previously reduced to practice or that any testing has been performed. Likewise, unless stated otherwise, use of verbs in the past tense is not intended to indicate or imply that the invention has been previously reduced to practice or that any testing has been performed.
(53) Although specific terms are employed herein, they are used in a generic and descriptive sense of only and not for purposes of limitation. Unless otherwise expressly defined herein, such terms are intended to be given their broad ordinary and customary meaning not inconsistent with that applicable in the relevant industry and without restriction to any specific embodiment hereinafter described. As used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one” or “single” or similar language is used. When used herein to join a list of the items, but does not exclude a plurality of items of the list.
(54) According to another approach of the present embodiments, a carbon fiber weave is used instead of a basalt mesh. In this embodiment the titanium layer is optional as are Kevlar wraps. According to this approach ceramic particulate reinforcement is added to the molten aluminum that is cast.
(55) The ceramic particulate reinforcement, by way of example, may be silicon carbide, boron carbide ceramic and combinations thereof in the range of about (or equal to) 1 to 60% by volume of the molten metal cast; preferably 30 to 60% and most preferably 40-50% by volume of the molten metal cast. In production, the ceramic particles can be dry mixed with aluminum alloy powder in a rotary batch or V mixer prior to heating and casting of aluminum alloy. The ceramic particulate size can be in the range of about 3-44 microns, and preferably in the range of about 6-20 micron.
(56) An exemplary armor plate of this embodiment is detailed in the following table
(57) TABLE-US-00002 System Assembly- NIJ 0101.06 Thickness, Area, Weight Weight M Threat Level III in ft2 ft2, lbs Torso, lbs Armor Cover- Polyurea 0.03 1 0.15 0.11 Spray Coat Aluminum MMC with 0.3 1 4.56 3.48 Silicon Carbide Reinforcement Thermoplastic Adhesive 0.01 1 0.02 0.02 Dyneema HB50 Ultra 0.3 1 2.38 1.82 High Molecular Weight Polyethylene Trauma Reduction Foam, 0.25 1 0.13 0.10 Closed Cell Armor Cover- Polyurea 0.03 1 0.15 0.11 Spray Coat Totals 0.92 7.39 5.65
(58) An Exemplary design lay-ups may include the following layers with examples of each:
(59) Armor cover—1000D Nylon, Polyurea spray (truck liner coating)
(60) Foam for ceramic durability—open cell foam at 0.25″ thick
(61) Ceramic strike face—Hot Presseed B4C, Sintered SiC, Aluminum Oxide, Hardened Steel
(62) Fiber composite backing—UHMW Poyethylene, Aramid (Kevlar), E-glass
(63) Foam for trauma reduction—closed cell foam at 0.25″ thick
(64) A ceramic strike face according to one approach of the present embodiments provides for threat levels up to NIJ Type (Lead core and some mild steel core bullets) and provides a significant improvement of prior art standard ceramic material with a metal matrix composite that includes an aluminum matrix with ceramic particle reinforcements cast over a carbon fiber weave on the rear side of the strike face material. A configuration of the material is shown as plate 522i in
(65) Aluminum is comparatively soft and elastic versus steel and ceramics used in the armor industry. Through the above matrix configuration, the ceramic increases plate hardness combined with the carbon fiber weave to improve stiffness. Trials suggest 20-40% by volume ceramic particulates dramatically change the hardness of the aluminum matrix. While the addition of a double layer of carbon fiber (areal density of 8.4 oz/yd2) when bonded to the aluminum matrix has significantly improved stiffness over prior art plates.
(66) Ballistic test were performed on two exemplary plates of the present embodiment as follows:
(67) Al 357 alloy cast on 2 layers of woven carbon fiber, samples were post heat treated
(68) Al40 SiC (reinforced aluminum alloy with 40% by volume Silicon Carbide) cast on 2 layers of woven carbon fiber
(69) Results Summary:
(70) Al357 alloy failed versus the level 3 threat with holes equal the diameter of the bullet
(71) Al40SiC stopped the level threat 3 threat with fracture mechanics different than traditional alloys (more brittle versus elastic failure)
(72) The test results demonstrate plates wherein aluminum to be the predominant material in a strike face allowing for lower weights than steel, less brittle (more durable) than ceramics at a cost point lower than ceramics.
(73) Thus, one aspect of the invention according to one approach includes a process for embedding a reinforcement fiber mesh such as, but not limited to, carbon fiber within a cast metal alloy, such as but not limited to, aluminum 6061 or 7075 alloy. Other base metals may be used for enhanced performance characteristics. Within this embodiment, the mesh may be suspended within the mold prior to casting and held in place during casting with metal standoffs or nibs or caplets or other types of spacers to help to maintain the position of the reinforcement to ensure coverage at both sides of the reinforcing material. Following the casting process, the plate is allowed to cool and removed from the mold. In one embodiment, the plates can be prepared with a finish edge treatment such as weld. In a preferred embodiment, the finish edge can be infused with a resin. Depending on the targeted threat level, a layered backup system may be incorporated in some embodiments having of a series of ballistic fabric materials such as a ballistic foam or an aramid fiber sold under the tradename KEVLAR (by DuPont) or any various types of ultra-high-molecular-weight polyethylene (UHMWP) polymers.
(74) The present embodiments provide several advantages over the known art. One key advantage is the comparative lightweight nature of the product with enhanced strength-to-weight performance of the assembly. This factor will allow military, police and security personnel to wear the protective gear for longer periods of time without additional strain of carrying added weight. Another advantage is its ability to potentially withstand multiple ballistic rounds. This innovation will allow soldiers, police or other security forces to remain engaged in conflict without the immediate need to take cover, retreat, or otherwise disengage in order to replace the damaged gear. And yet another advantage is its ability to absorb ballistic rounds received at an angle (its “obliquity”) (e.g., 0 to about 20 degrees from perpendicular) rather than ricocheting the bullet to potentially cause additional harm once deflected. For example, steel-based armor plates can frequently deflect bullets into the wearer's arm, torso or neck, or into a fellow soldier in an adjacent position. Capturing a bullet round enhances the safety of those seeking protection. The composite nature of the reinforced metal further improves flexibility, strength and resistance to deformity and failure.
(75) According to another approach, a wearable-enhanced-protective-system (WEPS) can be a laminated series of layers functioning homogeneously to mitigate Level 3A ballistic threats. These can include 9 mm FMJ, 0.357 SIG/FMJ and 44 MAG/SJHP as well as the 5.52 FMJ Rifle Round shot at 49 feet from an AR15 Assault Rifle and 7.62×51 mm M80 ball gives a Level 3 Rating based on National Institute of Justice (NIJ) Criteria. The WEPS system of the current embodiments can be a series of laminations and coatings.
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(82) While the embodiments have been described in conjunction with specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, the present embodiments attempt to embrace all such alternatives, modifications and variations that fall within the spirit and scope of the appended claims. Throughout this specification and the drawings and figures associated with this specification, numerical labels of previously shown or discussed features may be reused in another drawing figure to indicate similar features.