MXPA00010280A - Frangible metal bullets, ammunition and method of making such articles - Google Patents

Abstract

A frangible metal article such as a bullet and a method for making it. The frangible metal article is formed from a mixture of metal particles and metal or metalloid binder material which is compacted into the desired shape, heated to a temperature above that needed to form at least one intermetallic compound but below the temperature of joining of the metal particles by sintering and below the temperature of formation of substantial amounts of a ductile alloy of the metal of the particles and the metal or metalloid binder material and then cooled. When such articles are formed into bullets they have sufficient strength to maintain their integrity during firing but disintegrate into powder on impact and can be formulated to be lead-free.

Description

FRAGILE METAL BULLETS, AMMUNITION AND METHOD OF MANUFACTURING THESE ITEMS RELATED REQUESTS This is a divisional application of United States Patent Application Serial No. 09 / 063,924, filed on April 22, 1998.

FIELD OF THE INVENTION The present invention relates to fragile metal articles and, in particular, fragile bullets which have particular use in target shooting and / or training applications. Indoor and outdoor shooting applications benefit from the absence of dust as well as the characteristics of fragility (rupture). Fragile bullets are well known for these uses. These are characterized by the use of metallic powder that is consolidated into a bullet and has sufficient strength to preserve its integrity during firing, while fragmenting on impact against a solid object that has sufficient mass and rigidity to fracture the bullet.

BACKGROUND OF THE INVENTION Conventional full-density, cast, die-cut, copper-plated or copper-coated lead bullets are also used in indoor firing ranges and for training. To protect the shooters against rebounding, a "bullet trap" is usually required to stop the projectile and any resulting fragments from injuring shooters. In addition, the walls of the firing range or training facilities may be covered with rubber or some other projectile absorbent material to stop the occasional bullet fragments that bounce off. In this way, the cost of building and maintaining target shooting / indoor training is substantial. In addition, even using bullet traps and rebound absorbent materials in the walls, occasionally a bounce will somehow overcome these systems and injure a shooter. Firing lead bullets can cause the emission of lead dust suspended in the air, which is introduced into the atmosphere. This requires the implementation of elaborate ventilation systems and may require that people working in these facilities undergo blood monitoring programs to determine the amount of lead in their bloodstream. The accumulation of spent lead bullets and bullet fragments must be disposed of properly and regulations related to the disposal of lead waste are becoming increasingly complex. In this way, the generation of lead dust and the accumulation of spent lead bullets and fragments, causes environmental problems and has the potential for serious health problems. For a long time a material has been looked for to use it like bullet, which does not contain lead. One problem with the replacement of lead in the ammunition is that the replacement material must be heavy enough, so that the ammunition that uses these bullets, when used in automatic and semiautomatic weapons, makes the weapon carry out its cycle of I work in an appropriate way. The main criteria regarding the ability of a discharge with automatic or semi-automatic weapons, is the amount of energy that the ammunition delivers to the mechanism of completion of the cycle. For some types of weapons, this energy is supplied by the expanding gases that push back the cartridge cap. For other weapons, the recoil movement is used and still in other weapons, the high pressure gases are connected, through a port inside the barrel, with a mechanism that carries out the work cycle of the firearm. All firearms are designed to work with bullets and propellants (gunpowder) that produce certain characteristics of pressure against time. The use of a lighter bullet can cause problems during the operation of a semiautomatic or automatic weapon, if the energy transfer is too low to supply the mechanism with the energy necessary to carry out the work cycle. While the energy can be increased by the use of additional propellants or different types of propellants, this is not desirable because the characteristics of this training broadside would be significantly different from the ammunition that conventional bullets and propellants have. Furthermore, to replace the lead of a bullet, the selected material must have a sufficiently large specific weight, so that the mass of the resulting bullet is compatible with the propellants that are commercially available. It is not economically feasible to develop lead-free ammunition, when it is necessary to develop a propellant or other special compound. In addition, a lead-free training discharge should break into small particles when it hits a hard surface. The individual particles are then very light to transport enough energy to be dangerous. On the other hand, these bullets must be strong enough to withstand the high accelerations that occur during firing, sufficiently ductile to engage the barrel scratch and durable enough to retain markings or scratch identification markings, as required. require government agencies. Practical and training discharges using combinations of resinous binders and metal powders have not proved, in general, to be satisfactory, due to the uncontrollable characteristics of brittleness, insufficient strength, an increase in deposits or incrustation in the gun barrel , a decrease in the longevity of the cannon and the inability to retain or receive the engraving of the scratched barrel through which they shot.

SUMMARY OF THE INVENTION In accordance with the foregoing, the present invention is directed to a fragile metal bullet and to a method for manufacturing it, which in important ways save one or more of the limitations and disadvantages of the prior art. The additional features and advantages of the invention will be set forth in the following description and will be partially apparent from the description or may be learned by practicing the invention.

The objectives as well as other advantages of the invention will be appreciated and achieved by the article and the method particularly indicated in the written description and in the claims thereof, as well as in the attached drawings. To obtain these and other advantages and, in accordance with the purpose of the invention, as incorporated and broadly described, the present invention is directed to a fragile metal bullet and to a method for manufacturing it. The bullet comprises a multitude of metal particles and a brittle binder. Preferably, the brittle binder consists essentially of at least one intermetallic compound formed from the metal particles and a binder-forming material. The binder-forming material is a metal or a metalloid which forms a brittle binder former at a treatment temperature below the bonding temperature of the metal particles, lower than the formation temperature of significant amounts of a ductile metal alloy of the metal particles and of the binder-forming material and above the temperature at which the binder-forming material and the metal particles form at least one intermetallic compound that binds the metal particles in a coherent and fragile article. According to the method for manufacturing the article, the metal particles and the powder binding material are compacted to the shape of the metal article, then heated to the treatment temperature for a sufficient time to form at least one intermetallic compound brittle, and then cool to form the fragile metal bullet. In further aspects of the invention, the metal particles are metals or alloys of base metals, selected from: copper, iron, nickel, gold, silver, lead, chromium and their alloys and, preferably, copper or copper-based alloys and the Binder-forming material consists essentially of materials selected from: tin, zinc, gallium, germanium, silicon, arsenic, aluminum, indium, antimony, lead, bismuth and their alloys and, preferably, tin or tin base alloys. Another embodiment is a fragile metal bullet comprised of a multitude of non-sintered metal particles and at least one binder of intermetallic compound that binds the metal particles to form the metal bullet. In additional aspects of this embodiment, the binder has the microstructure of a brittle, porous material and the final product treated using this binder has a transverse break strength of less than 13,000 psi. Fragile bullets that have these properties fracture into a multitude of particles thanks to the brittle failure of the binder, so that the fracture absorbs most of the bullet's kinetic energy. In still another embodiment, the invention is a method for manufacturing a fragile metal bullet, comprising the steps of: forming a mixture comprising metal particles, for example, copper and copper alloys and a metal binder forming material, the material that metallic binder form comprises metals and alloys, arranged to form intermetallic compounds with the metal of the metal particles, for example, tin and tin alloys. The composition of the mixture is arranged so as to form a brittle binder at a treatment temperature lower than the junction temperature of the metal particles, lower than the formation temperature of significant amounts of a ductile metal alloy of the metal particles and of the metal binder-forming material but above the temperature necessary to form at least one intermetallic compound of the metal and the metal binder-forming material. The mixture is compacted to form a P1164 compacted in formed green, is heated to the treatment temperature for sufficient time to form an effective amount of at least one intermetallic compound, thereby forming a shaped metal precursor and returning the shaped metal precursor to room temperature to form the metallic article. In one aspect of this embodiment, the dimensions of the compacted shaped green are within 0.2% of the dimensions of the fragile metallic article. In additional embodiments of the method of the invention, the dimensions of the compacted green are within 0.2% of the dimensions of the fragile metal bullet. It will be understood that both the above general description and the following detailed description are exemplary and explanatory and are intended to provide a further explanation to the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide further understanding of the invention and are incorporated in and constitute a part of this specification and together with the description serve to explain the P1164 principles of the invention. Figure 1 is a cross-sectional view of a central percussion cartridge including a bullet of the invention. Figure 2 is a side view of a bullet of the discharged invention, illustrating the retention of the scratch engraving of the barrel.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Reference will now be made to the preferred embodiments of the invention. In accordance with the present invention, a fragile metal bullet comprising a multitude of metal particles joined by a binder is provided. The binder-forming material is arranged to form a transient liquid phase at a treatment temperature lower than the bonding temperature of the metal particles through sintering, lower than the formation temperature of a significant amount of a ductile alloy of the material which binder forms and metal particles but higher than the formation temperature of at least one intermetallic compound of the metal of the metal particles and of the binder-forming material. For the purposes of this invention, a significant amount of this ductile alloy is an amount that makes the resulting structure ductile to the point where the final treated bullet is no longer brittle. For example, in an embodiment where the metallic particles are copper and the binder-forming material is tin, a treatment temperature of 230 to 430 ° C produces a transient liquid phase, initially only of liquid tin, with no appreciable amount of binding copper particle / copper particle. The liquid tin subsequently receives the copper and forms a first intermetallic compound in solid form on the surface of the copper particles. The diffusion of copper into and through the initial intermetallic compound forms additional intermetallic compounds and, depending on temperature and time, the total amount of liquid tin can be transformed into a solid comprised of at least one copper and tin intermetallic compound. If the article cools before these transformations end, a portion of the tin may solidify in the form of a metal, although the compound or intermetallic compounds may solidify on the surface of the copper particles. The amount of the intermetallic compound or compounds relative to the amount of the solid tin will determine whether the article is brittle or ductile. In addition, the treatment time and temperature should be such that there is no appreciable formation of the P1164 alpha bronze phase in the microstructure. If there were appreciable amounts of the alpha bronze phase, it would drastically reduce the fragility of the bullet by significantly increasing the ductility and resistance to the transversal breakage of the treated article. The metal particles and the binder-forming material are agglomerated by compaction in the form of a bale and then heated to the treatment temperature for a sufficient time to form an effective amount of the transient liquid phase of the binder and then cooled to form the bullet. An effective amount of the transient liquid phase of the binder-forming material is sufficient to adhere the metallic particles in a coherent body when the transient liquid phase of the binder forms at least one intermetallic compound. This amount does not prevent smaller amounts of metallic particle / metallic particle from joining, although the mechanical properties of the metallic article are determined to a greater extent by the mechanical properties of the binder than by the strength of any metal particle / metallic particle bond in the metallic article. In a preferred embodiment of the invention, the metal article is a fragile, lead-free metal bullet. The metal particles are not sintered and the metal binder is a brittle intermetallic compound. For the purposes of the present invention, the term "brittle" includes materials which, at ambient temperatures, exhibit low fracture toughness, low ductility or low resistance to crack propagation. Another preferred embodiment of the invention is a frail, lead-free metal bullet loaded in a cartridge. As embodied in Figure 1, a conventional central percussion cartridge utilizing the bullet of the present invention is depicted, however, the invention can also be used in edge percussion cartridges (not shown). The bullet 10, here a bullet of 9 millimeters of rounded tip, is inserted in the mouth 12 of the cap. The bushing 14 can be crimped (deformed inward) in the mouth 12 of the bushing to assist in retaining the bullet at the desired insertion depth within the bushing 14. The bullets of the present invention have sufficient strength and ductility to withstand the crimping operation without fracturing during the link. The bushing further includes a primer cavity 16 into which a separate primer 18 can be inserted. The bushing shown in Figure 1 is the typical bushing with straight walls of ammunition for P1164 gun. The bullets of the present invention are also useful as ammunition for rifle and for these ammunition, the cap can be a cartridge with a "bottleneck" (not shown), wherein the mouth of the cap has a smaller diameter than that of the body of the cap. cartridge cap. The propellant (gunpowder) 20 is placed in the body of the cap 14 of the cartridge. It is preferred that the primer 18 be lead-free. In this way, if the bullet 10 is also lead-free, when the cartridge is fired, no lead will be generated. These primers are manufactured by CCI Industries of Lewiston, Idaho, E.U.A. and are designated as Cleanfire® primers. As incorporated herein, the primer 18 includes a lead-free primer composition 22, however, a percussion cartridge on the edge would have this composition within the edge of the cartridge itself (not shown). Preferably, the metal particles of the invention consist essentially of base metals or base metal alloys, selected from copper, iron, nickel, gold, silver, lead, chromium and their alloys, preferably copper, iron, nickel and chromium and with the highest preference, copper and copper alloys. In a further preferred embodiment of the invention, the binder-forming material consists essentially of a metal, metals, base metal alloys, metalloids and mixtures and P1164 alloys thereof, which will form at least one intermetallic compound with the metal of the metal particles. These materials can be selected from: tin, zinc, gallium, germanium, silicon, arsenic, aluminum, indium, antimony, lead, bismuth and their mixtures and alloys, most preferably, tin and tin alloys. An important feature of the present invention is that the fragile metal bullet, while maintaining its integrity during firing, becomes a multitude of particles thanks to the fragility failure of the brittle binder to the impact of the bullet against an object, avoiding in this way the problems of rebound that are found when using conventional castings or die-cut. This fracturing of the fragile metal bullet into a multitude of particles additionally absorbs most of the bullet's kinetic energy, essentially eliminating the possibility of rebounding the bullet or pieces thereof. Due to the porous microstructure of the metal article of the invention, it can also retain various lubricants, such as molybdenum disulfide, Teflon® and carbon, to facilitate its passage through the gun barrel. The microstructure of these materials after the thermal treatments suitable for the particular metallic particle / binder combination is characterized by solid metallic particles bonded together by the binder material consisting essentially of at least one intermetallic compound. These systems are preferred, because they render the thermally treated material fragile in an appropriate manner. The binder can be completely dense or porous. In addition to the mechanical properties described above, the fragile metal bullet of the invention possesses sufficient strength due to the binder used, to support the manual or automatic loading of the bullet into a cartridge, maintain its integrity during firing and receive and retain the engraving of the scratch of the gun barrel from which it was fired, as shown in Figure 2. Figure 2 depicts a schematic view of a 9 millimeter pistol bullet 30 with grooves 32 on its outer peripheral surface. These grooves 32 are formed by scratching the gun barrel as the bullet passes through the barrel and are typically characteristic of the particular barrel that fired the bullet. This last characteristic is of particular interest in compliance with the laws, since it is considered essential that it be possible to identify the particular weapons from which the bullets have been unloaded.

P1164 In accordance with the present invention, the fragile metal bullet is formed by a method comprising: forming a mixture of the metal particles and binder-forming materials to form a transient liquid phase at a treatment temperature lower than the sintering temperature of neck growth of the metal particles and above the temperature at which at least one metal intermetallic compound of the metal particles and the binder-forming materials is formed. The mixture is then compacted under pressure using the known compaction techniques, such as matrix compaction, rotary screw compaction, isostatic pressing, to form a shaped green compaction. The green compact is heated to the treatment temperature for a sufficient time to form an effective amount of the transient liquid phase and then at least one intermetallic compound, thereby forming a shaped metal precursor. The shaped metallic precursor is then returned to ambient temperature to form the metal article of the invention, which may be a fragile, lead-free metallic bullet. The treatment temperature and the duration of the heating will, of course, depend on the selection of metal particles and the binder-forming material. The treatment temperature will be below the temperature at which the metal particles are bonded together by sintering, below the formation temperature of significant amounts of a ductile metal alloy of the metal particles and the binder-forming material and above the temperature at which at least one intermetallic compound of the metal of the metal particles and of the binder-forming material is formed. This has the beneficial effect that a very small dimensional change occurs as a result of the thermal treatment of the compact in green. In the preferred embodiment of the invention, the metal particles consist essentially of copper and the binder-forming material consists essentially of tin and that compacted in green is heated to a temperature in the range of 150 to 430 ° C for up to sixty minutes to form a brittle binder consisting essentially of at least one intermetallic compound. As indicated above, a particular advantageous aspect of the present invention is that the brittle metal article essentially retains the shape and dimensions of the green compact. In this way, the shape and dimensions of the tool that forms the compact in green formed can be the same as P1164 the desired final product. According to the invention, the dimensions of the fragile metal article are within 0.2% of the dimensions of the compact in green formed. The following examples are illustrative of the invention.

EXAMPLE 1 In accordance with the invention, several fragile metal bullets were formed, using a commercial bronze premix (PMB-8, OMG Americas, Research Triangle Park, North Carolina, USA) The components of the premix were 89.75 weight percent of copper particles, 10 weight percent tin particles and 0.25 weight percent zinc stearate lubricant. The lubricant was present to help the compaction and expulsion of the compact in green and was practically eliminated during the subsequent thermal treatment. The premix had particle sizes of approximately 8% greater than the 250 mesh, approximately 30% larger than the 325 mesh, where the remainder was smaller than the 325 mesh. The mixture was compacted using a standard matrix of straight walls in a press Mechanical that later was determined that exerted a gross load of approximately 20 tons. The matrix converted the P1164 mixed in several compacted in green with the size and configuration of a 9 mm bullet. The compacts in green were subsequently heated to a temperature of 260 ° C for 30 minutes under a nitrogen atmosphere and, at this time, the total weight of the binder had been transformed into a transient liquid binder phase and, finally, into at least one copper and tin intermetallic compound. The treated compacts were then cooled to room temperature, resulting in 9-millimeter bullets with a weight of 105 grains (6.80 grams) with a deviation less than 0.1% of the original dimensions of the compacted green. The bullets were loaded in brass cartridges with 4.5 grains of Hercules Bullseye® powder and crimped. The resulting ammunition was tested by firing it from several different weapons (which included semi-automatic and fully automatic weapons) against a 0.25-inch steel barrier. The munitions worked without malfunctioning, they fed, fired and ejected without problems. When hit against the barrier, the bullets disintegrated completely into a fine powder.

EXAMPLES 2 - 4 The same material converted to the bullets of Example 1, became bars for the standard test P1164 of resistance to transversal breakage. Samples were tested in the green state (ie, compacted but without heat treatment) (Example 2), after the same heat treatment of Example 1, at a temperature of 260 ° C for 30 minutes under nitrogen (Example 3) ) and after a heat treatment at a temperature of 810 ° C for 30 minutes under a nitrogen atmosphere (Example 4). The following properties were determined: density, percentage of dimensional change with respect to the size of the matrix (as described in ASTM B610, MPIF 44 or ISO 4492), Rockwell hardness H (HRH) and resistance to transverse fracture (TRS per its acronym in English), in units of pounds per square inch (psi) as determined in accordance with ASTM B528, MPIF 41 or ISO 3325). The Rockwell H hardness scale is based on the use of a 1/8 inch ball indenter and a 150 kg load (ASM Metals Handbook).

Example Density Change in size HRH (average) TRS 2 7.26 g / cc 0.14% 73.7 3,651 psi 3 7.27 g / cc 0.07% 94.8 12,710 psi 4 6.53 g / cc 2.53% 52.7 32.625 psi The above data indicate that the mode using a mixture of approximately 90/10 copper / tin, compacted in conventional manner and after P1164 heat treated at a temperature of 260 ° C for 30 minutes, produces an acceptable brittle bale when the transverse tear strength of the treated article is about 13,000 psi or less. Resistance to transverse fracture greater than 13,000 psi is operable for fragile bullets although not preferred. The metallography on other samples confirmed that, in the copper / tin system, the tin initially melted and the liquid tin infiltrated the spaces around the copper particles. The copper then diffused into the liquid tin and formed at least a first intermetallic compound that solidified as a layer on the copper particles. Liquid tin may still be present and it is believed that the first intermetallic compound may melt as more copper and tin diffuse into the first intermetallic compound to form a second intermetallic compound. At the treatment temperature, the tin continues to diffuse towards the copper particles, forming voids in the binder. Depending on the amount of tin in the mixture, the treatment temperature and the time at the treatment temperature, the elemental tin will disappear and at least one intermetallic compound will be formed. These intermetallic compounds have low ductility, low fracture toughness and low P1164 resistance to the propagation of cracks. Because these materials comprise the binder that binds the metal particles and the metal particles are not otherwise bound by a ductile material (either by means of the particle / particle bond or the bond with a ductile binder), the article thus united is fragile. In addition, the volume changes associated with the creation of the intermetallic compounds and the porosity can be manipulated to form articles that do not dimensionally change significantly during the formation of the bound article. The copper / tin phase diagram indicates that several different intermetallic compounds can be formed at equilibrium. While not limiting the invention to the disclosed embodiment and not wishing to be restricted by theory, it is believed that the intermetallic compound present in the preferred embodiment is that in a phase equilibrium diagram known as the eta phase. The heat treatments described herein may or may not result in equilibrium structures although the species of the intermetallic compound or intermetallic compounds or the existence of non-equilibrium phases is not as important for the invention as are the effects that these materials , when used as binders, they have on the properties P1164 and the dimensions of the articles formed from them. In this way, the binders of the invention can be mixtures of intermetallic compounds, a single intermetallic compound or a brittle mixture of some phase with an intermetallic compound. Additional advantages and modifications to the disclosed modalities may occur to those skilled in the art. Subsequently, it can be found that specific intermetallic compounds or combinations thereof are advantageous. These materials are within the scope of the invention. The invention, in its broader aspects, is therefore not limited to the materials, details, modalities and specific examples shown and described. In accordance with the foregoing, deviations to those specifically disclosed may be made, without deviating from the scope of the invention as defined by the appended claims and their equivalents.

P1164

Claims (23)

1. CLAIMS: 1. A fragile metal bullet comprising: a multitude of metal particles; a brittle binder for joining metal particles; the binder consists essentially of at least one intermetallic compound.
2. 2. The brittle metal bullet according to claim 1, wherein the metal particles and a metal or metalloid binder forming material are compacted into the shape of a bale, then heated to a treatment temperature for a sufficient time to form, with cooling, an effective amount of at least one brittle intermetallic compound and then cooled to form the brittle metal bullet.
3. The brittle metal bullet according to claim 2, wherein the metal particles consist essentially of metals or base metal alloys selected from the group consisting of: copper, iron, nickel, gold, silver, lead, chromium and their alloys.
4. The brittle metal bullet according to claim 2, wherein the metallic or metalloid binder forming material consists essentially of a material selected from the group consisting of: tin, P1164 zinc, gallium, germanium, silicon, arsenic, aluminum, indium, antimony, lead, bismuth, their mixtures and their alloys.
5. The brittle metal bullet according to claim 2, wherein the brittle binder consists essentially of at least one intermetallic compound of a first metal selected from the group consisting of: copper, iron, nickel, gold, silver, lead and chromium and a second metal or metalloid selected from the group consisting of: tin, zinc, gallium, germanium, silicon, arsenic, aluminum, indium, antimony, lead and bismuth.
6. 6. A fragile and lead-free metal bullet, comprising: a multitude of metal particles, the metal is selected from the group consisting of: copper, copper-based alloys, iron, nickel and chromium a material that forms metal or metalloid binder arranged to form a brittle binder comprised of at least one intermetallic compound at a treatment temperature lower than the metal particle binding temperature with metal particle or that of formation of significant amounts of a binder / metal particle alloy.
7. 7. The brittle metal bullet according to claim 6, wherein the metal particles and the binder-forming material are compacted in the form of P1164 bullet, then heated to the treatment temperature for a sufficient time to form, with cooling, at least one intermetallic compound and then cooled to form the metal bullet.
8. 8. The fragile metal bullet according to claim 7, wherein the metal particles consist essentially of copper or copper-based alloys.
9. 9. The brittle metal bullet according to claim 8, wherein the binder-forming material consists essentially of tin or tin-base alloys.
10. The fragile metal bullet according to claim 8, wherein the binder-forming material consists essentially of tin and the brittle binder comprises a copper-tin intermetallic compound.
11. 11. The brittle metal bullet according to claim 10, wherein the copper-tin intermetallic compound consists essentially of the eta phase.
12. 12. A brittle metal bullet comprising: a multitude of non-sintered metal particles; an intermetallic compound binder that bonds the metal particles together to form the bullet P1164 metal.
13. 13. The brittle metal bullet according to claim 12, wherein the binder has a microstructure that is characterized as a porous and brittle metal having at least one intermetallic compound that bonds the adjacent metal particles.
14. The fragile metal bullet according to claim 12, wherein the metal bullet consists of a material having a transverse breaking strength of less than 13., 000 psi.
15. 15. The brittle metal bullet according to claim 12, wherein the fragile metal bullet is converted into a multitude of particles by means of the brittle failure of the binder.
16. 16. The brittle metal bullet according to claim 15, wherein the fracture of the fragile metal bullet in a multitude of particles absorbs most of the kinetic energy of the bullet.
17. 17. A method for manufacturing a fragile metal bullet, the method comprising the steps of: forming a mixture comprising metal particles and a metal or metalloid binder-like material arranged to form at least one intermetallic compound at a treatment temperature less than the junction temperature of the metal particles and the P1164 formation of significant amounts of a ductile alloy of the metal particles and the binder-forming material; compact the mixture to form a compact in green with the shape of the bullet; heating the compacted green at the treatment temperature for a sufficient time to form an effective amount of at least one intermetallic, brittle compound, thereby forming a shaped metallic precursor and returning the metal precursor to room temperature to form the bullet fragile metal.
18. 18. The method for manufacturing a fragile metal bullet according to claim 17, wherein the metal particles consist essentially of copper and the binder-forming material consists essentially of tin.
19. The method for manufacturing a fragile metal bullet according to claim 17, wherein the dimensions of the compacted green are within 0.2% of the dimensions of the fragile metal bullet.
20. 20. A lead-free cartridge comprising: a cartridge sleeve having a neck; a lead-free primer composition; a propellant inside the cartridge and P1164 a lead-free, fragile metal bullet, comprised of a multitude of non-sintered metal particles bonded with a brittle binder consisting essentially of at least one intermetallic compound formed from a binder-forming material, the metal particles comprise a metal selected from the group consisting of: copper, iron, nickel, chromium, tungsten and their alloys, the bullet is in the neck of the cap.
21. The cartridge according to claim 20, wherein the binder-forming material comprises a material selected from the group consisting of: tin, zinc, gallium, germanium, silicon, arsenic, indium, aluminum, antimony, bismuth and mixtures thereof.
22. 22. The cartridge according to claim 20, wherein the cartridge is a central percussion cartridge having a primer cavity and in it has a primer.
23. 23. The cartridge according to claim 20, wherein the cartridge is a percussion cartridge on the edge. P1164