Enhanced metal-metal-matrix composite weapon barrels and ways of making the same

Abstract

Weapon barrels are disclosed which offer improved thermal performance and rigidity with no, minimal or negative weight increase. In general the barrel comprises a barrel core surrounded by a lightweight, thermally conductive sleeve made from metal-matrix composite (MMC) materials, also referred to as metal-matrix material. The increased diameter of the sleeve improves the barrel's stiffness and the sleeve's thermal conductivity and distributes the heat more evenly along the barrel. Manufacturing and joining techniques are disclosed as well as materials and material combinations that allow the barrel to perform at high cadence over the whole temperature range the barrel is used. Hot spots may be reduced and more surface area can contribute to heat dissipation. The increased diameter also allows integration of phase changing and/or vibration dampening materials, which further enhance performance.

What is claimed is: 
     
         1 . A gun having a composite gun barrel, wherein the barrel comprises:
 an inner core; and at least one outer sleeve that surrounds the circumference of the core over a length of the core, the sleeve being joined to the core over such length.   
     
     
         2 . The gun of  claim 1 , wherein the inner core comprises a material selected from the group consisting of a ferrous alloy, a non-ferrous alloy, a ceramic, a bonded ceramic or a cemented carbide. 
     
     
         3 . The gun of  claim 1 , wherein the outer sleeve comprises a metal or metal-matrix composite material with a density of less than 5 g/cm 3 . 
     
     
         4 . The gun of  claim 3 , wherein the metal-matrix composite material comprises a matrix material selected from the group consisting of aluminum, scandium, francium, titanium, lithium, beryllium, magnesium, yttrium, calcium, potassium, sodium, barium their alloys, metallic glasses and intermetallic phases, and wherein the metal-matrix composite material further comprises a filler material selected from the group consisting of carbon nanotubes, graphene, carbon fibers, copper, gold, silver, aluminum nitride, boron nitride, boron nitride nanotubes, beryllium oxide, beryllium, diamond and silicon carbide. 
     
     
         5 . The gun of  claim 1 , wherein the sleeve comprises a star-shaped cross-section having a plurality of points separated by arcuate segments. 
     
     
         6 . The gun of  claim 1 , wherein the barrel comprises a sleeve with annular surface structure. 
     
     
         7 . The gun of  claim 1 , wherein the sleeve extends over a length of the barrel from the muzzle to the end of the breach. 
     
     
         8 . The gun of  claim 1 , wherein the sleeve extends over a length of the barrel from the muzzle to the opening of the breach. 
     
     
         9 . The gun of  claim 1 , wherein the sleeve extends over a length of the barrel from an end of the breach to a plane that is offset from the end of the muzzle such that the core protrudes from the sleeve at the muzzle. 
     
     
         10 . The gun of  claim 1 , wherein the sleeve comprises a plurality of longitudinal voids spaced at regular angular intervals about the sleeve. 
     
     
         11 . The gun of  claim 10 , wherein the voids comprise cylindrical voids, and wherein a filler material is disposed within the voids. 
     
     
         12 . The gun of  claim 10 , wherein the voids comprise arcuate segments, wherein a filler material is disposed within the voids, and wherein the filler material comprises at least one of a viscous damping material and a phase change material. 
     
     
         13 . The gun of  claim 1 , wherein the sleeve comprises a plurality of fins spaced at regular angular intervals about the circumference of the sleeve, each fin including a filler material disposed therein, the filler material being selected from the group consisting of a phase change material and a viscous damping material. 
     
     
         14 . A method of manufacturing a gun barrel comprising an inner core and at least one outer sleeve that surrounds the circumference of the core over a length of the core, the sleeve being joined to the core over such length, the method comprising:
 providing the core and the sleeve, wherein an internal diameter of the sleeve is smaller than an external diameter of the core;   heating the sleeve to a first temperature that is greater than the temperature of the core such that the internal diameter of the sleeve is slightly less than the external diameter of the core at the first temperature;   pressing the core into the internal diameter of the sleeve; and   allowing the core and the sleeve to reach thermal equilibrium.   
     
     
         15 . The method of  claim 14 , further comprising pulling the core into the internal diameter of the sleeve. 
     
     
         16 . The method of  claim 14 , further comprising stabilizing the sleeve and core within a mold prior to pressing the core into the internal diameter of the sleeve. 
     
     
         17 . The method of  claim 14 , further comprising applying an intermediate layer to an external surface of the core prior to pressing the core into the internal diameter of the sleeve. 
     
     
         18 . The method of  claim 14 , further comprising applying an intermediate layer to an internal surface of the sleeve prior to pressing the core into the internal diameter of the sleeve. 
     
     
         19 . The method of  claim 14 , wherein the core comprises an annular ridge, and wherein the sleeve comprises an internal annular groove that complements the annular ridge. 
     
     
         20 . The method of  claim 14 , wherein pressing the core into the internal diameter of the sleeve comprises aligning the annular ridge of the core with the annular groove of the sleeve. 
     
     
         21 . A method of manufacturing a gun barrel comprising an inner core and at least one outer sleeve that surrounds the circumference of the core over a length of the core, the sleeve being joined to the core over such length, the method comprising:
 providing the core and the sleeve, wherein an internal diameter of the sleeve is smaller than an external diameter of the core;   heating the sleeve to a first temperature that is greater than 250° C.; and   applying a pressure of at least 20 MPa to press the core into the internal diameter of the sleeve.