Whisker reinforced high fracture toughness ceramic threaded fasteners

Abstract

A high temperature fastener including a bolt and a nut, where the bolt and the nut are constructed of an aluminum oxide ceramic material reinforced with silicon-carbide crystal whiskers or silicon nitride.

1 . A fastener comprising:
 a blank, the blank being constructed of a ceramic material; and,   a screw threaded surface on the blank.   
     
     
         2 . The fastener of  claim 1 , further comprising:
 the ceramic material being an aluminum oxide ceramic material reinforced with silicon-carbide crystal whiskers in the aluminum oxide ceramic material.   
     
     
         3 . The fastener of  claim 1 , further comprising:
 the ceramic material being silicon nitride.   
     
     
         4 . The fastener of  claim 2 , further comprising:
 the screw threaded surface being a screw threaded exterior surface of the fastener.   
     
     
         5 . The fastener  claim 2 , further comprising:
 the screw threaded surface being a screw threaded interior surface of the fastener.   
     
     
         6 . The fastener of  claim 2 , further comprising:
 the blank being a first blank;   the screw threaded surface on the first blank being a screw threaded exterior surface of the fastener;   a second blank, the second blank being constructed of an aluminum oxide ceramic material reinforced by silicon-carbide crystal whiskers in the aluminum oxide ceramic material;   a screw threaded surface on the second blank; and,   the screw thread surface on the second blank being a screw threaded interior surface of the fastener.   
     
     
         7 . The fastener of  claim 4 , further comprising:
 a channel extending into an interior of the blank, the channel being surrounded by an interior surface; and,   the channel being a cooling channel.   
     
     
         8 . The fastener of  claim 4 , further comprising:
 a channel extending into an interior of the blank, the channel being surrounded by an interior surface; and,   the interior surface being a tool interface surface,   
     
     
         9 . The fastener of  claim 2 , further comprising:
 a percentage of the silicon-carbide crystal whiskers in the aluminum oxide ceramic material being in a range of 18% to 30%.   
     
     
         10 . A fastener comprising:
 a bolt, the bolt having a length;   a head at a first end of the length of the bolt;   a screw threaded exterior surface at a second end of the length of the bolt; and,   the bolt being constructed of ceramic material.   
     
     
         11 . The fastener of  claim 10 , further comprising:
 the ceramic material being an aluminum oxide ceramic material reinforced with silicon-carbide crystal whiskers in the aluminum oxide ceramic material.   
     
     
         12 . The fastener of  claim 10 , further comprising:
 the ceramic material being silicon nitride.   
     
     
         13 . The fastener of  claim 11 , further comprising:
 a nut, the nut having a screw threaded interior surface that extends through the nut, the screw threaded interior surface of the nut being complementary to the screw threaded exterior surface of the bolt; and,   the nut being constructed of an aluminum oxide ceramic material reinforced with silicone-carbide crystal whiskers in the aluminum oxide ceramic material.   
     
     
         14 . The fastener of  claim 11 , further comprising:
 the bolt having a center axis along the length of the bolt;   the head of the bolt and the screw threaded exterior surface of the bolt being at axially opposite ends of the center axis; and,   a channel extending axially into an interior of the bolt, the channel being a cooling channel,   
     
     
         15 . The fastener of  claim 11 , further comprising:
 the bolt having a center axis along the length of the bolt;   the head of the bolt and the screw threaded exterior surface of the bolt being at axially opposite ends of the center axis; and,   a channel extending into an interior of the bolt perpendicular to the center axis, the channel being a cooling channel.   
     
     
         16 . The fastener of  claim 11 , further comprising:
 the bolt having a center axis along the length of the bolt;   the head of the bolt and the screw threaded exterior surface of the bolt being at axially opposite ends of the center axis; and,   a channel extending axially into an interior of the bolt from the head of the bolt, the channel having an interior surface formed as a tool interface surface.   
     
     
         17 . The fastener of  claim 11 , further comprising:
 a percentage of the silicon-carbide crystal whiskers in the aluminum oxide ceramic material being in a range of 18% to 30%.   
     
     
         18 . A method of making a fastener comprising:
 creating a mixture of ceramic material powder;   simultaneously heating and pressurizing the mixture creating a solid blank; and   forming a screw threaded surface on the blank.   
     
     
         19 . The method of  claim 18 , further comprising:
 creating the mixture of ceramic material powder from aluminum oxide ceramic material powder and silicon carbide crystal whiskers disbursed in the aluminum oxide ceramic material powder.   
     
     
         20 . The method of  claim 18 , further comprising:
 creating the mixture of ceramic material powder from silicon nitride.   
     
     
         21 . The method of  claim 19 , further comprising:
 forming the screw threaded surface on the blank by machining the blank to form a screw threaded exterior surface on the blank.   
     
     
         22 . The method of  claim 19 , further comprising:
 forming a channel inside the blank by positioning an insert inside the mixture of aluminum oxide ceramic material powder and silicon-carbide crystal whiskers prior to simultaneously heating and pressurizing the mixture;   simultaneously heating and pressurizing the mixture creating a blank; and,   removing at least a portion of the insert from inside the blank.   
     
     
         23 . The method of  claim 22 , further comprising:
 removing at least a portion of the insert from inside the blank creating a tool interface interior surface inside a blank;   
     
     
         24 . The method of  claim 22 , further comprising:
 removing at least a portion of the insert from inside the blank creating a cooling channel inside the blank.   
     
     
         25 . The method of  claim 22 , further comprising:
 removing at least a portion of the insert from inside the blank creating a screw threaded interior surface inside the blank.   
     
     
         26 . The method of  claim 19 , further comprising:
 creating a mixture of aluminum oxide ceramic material powder and silicon-carbide crystal whiskers with a percentage of the silicon-carbide crystal whiskers in the mixture being in a range of 18% to 30% of the mixture.   
     
     
         27 . The method of  claim 19 , further comprising
 the fastener having a low cataycity and high emissivity.