Titanium-containing alloys and associated methods of manufacture

Abstract

Titanium-containing alloys are generally described. The titanium-containing alloys are, according to certain embodiments, nanocrystalline. According to certain embodiments, the titanium-containing alloys have high relative densities. The titanium-containing alloys can be relatively stable, according to certain embodiments. Inventive methods for making titanium-containing alloys are also described herein. The inventive methods for making titanium-containing alloys can involve, according to certain embodiments, sintering nanocrystalline particulates comprising titanium and at least one other metal to form a titanium-containing nanocrystalline alloy.

What is claimed is: 
     
         1 . A sintered nanocrystalline metal alloy, comprising:
 Ti; and   a second metal;   wherein:
 Ti is the most abundant metal by atomic percentage in the sintered nanocrystalline metal alloy, and 
 the sintered nanocrystalline metal alloy has a relative density of at least 80%. 
   
     
     
         2 . A sintered nanocrystalline metal alloy, comprising:
 Ti; and   a second metal;   wherein:
 the second metal and Ti exhibit a miscibility gap, and 
 the sintered nanocrystalline metal alloy has a relative density of at least 80%. 
   
     
     
         3 . A bulk nanocrystalline metal alloy, comprising:
 Ti; and   a second metal;   wherein:
 Ti is the most abundant metal by atomic percentage in the bulk nanocrystalline metal alloy, and 
 the bulk nanocrystalline metal alloy is substantially stable at a temperature that is greater than or equal to 100° C. 
   
     
     
         4 . A bulk nanocrystalline metal alloy, comprising:
 Ti; and   a second metal;   wherein:
 Ti is the most abundant metal by atomic percentage in the bulk nanocrystalline metal alloy, and 
 the bulk nanocrystalline metal alloy has an average grain size of less than 300 nm. 
   
     
     
         5 . A metal alloy, comprising:
 Ti; and   Mg;   wherein the metal alloy has a relative density of greater than or equal to 80%.   
     
     
         6 . The metal alloy of any one of the preceding claims, wherein the second metal comprises an alkaline earth metal. 
     
     
         7 . The metal alloy of any one of the preceding claims, wherein the second metal is selected from the group consisting of Mg, La, Y, Th, Sc, Cr, Ag, Fe, Mn, Cu, and Li. 
     
     
         8 . The metal alloy of any one of the preceding claims, wherein the second metal is Mg. 
     
     
         9 . The metal alloy of any one of the preceding claims, wherein the second metal is present in the nanocrystalline metal alloy in an amount of less than 40 atomic percent of the nanocrystalline metal alloy. 
     
     
         10 . The metal alloy of any one of the preceding claims, wherein the second metal is present in the nanocrystalline metal alloy in an amount of from 1 atomic percent to 40 atomic percent of the nanocrystalline metal alloy. 
     
     
         11 . The metal alloy of any one of the preceding claims, wherein the second metal is present in the nanocrystalline metal alloy in an amount of from 8 atomic percent to 32 atomic percent of the nanocrystalline metal alloy. 
     
     
         12 . The metal alloy of any one of the preceding claims, wherein Ti is present in the nanocrystalline alloy in an amount of at least 50 atomic percent. 
     
     
         13 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy is a dual-phase metal alloy. 
     
     
         14 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy further comprises a third metal. 
     
     
         15 . The metal alloy of any one of the preceding claims, wherein the second metal and Ti exhibit a miscibility gap. 
     
     
         16 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has an average grain size of less than 300 nm. 
     
     
         17 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has an average grain size of less than 150 nm. 
     
     
         18 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has an average grain size of less than 125 nm. 
     
     
         19 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has an average grain size of less than 100 nm. 
     
     
         20 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has a relative density of at least 80%. 
     
     
         21 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has a relative density of at least 85%. 
     
     
         22 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has a relative density of at least 90%. 
     
     
         23 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has a relative density of at least 95%. 
     
     
         24 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has a relative density of at least 97%. 
     
     
         25 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has a relative density of at least 99%. 
     
     
         26 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy is a bulk nanocrystalline metal alloy. 
     
     
         27 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy is substantially stable at a temperature that is greater than or equal to 100° C. 
     
     
         28 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy is substantially stable at a temperature that is greater than or equal to 300° C. 
     
     
         29 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy is substantially stable at a temperature that is greater than or equal to 500° C. 
     
     
         30 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy is substantially stable at a temperature that is greater than or equal to 700° C. 
     
     
         31 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy is substantially stable at a temperature that is greater than or equal to 800° C. 
     
     
         32 . The metal alloy of any one of the preceding claims, wherein Ti is at least partially soluble in the second metal. 
     
     
         33 . The metal alloy of any one of the preceding claims, wherein Ti and the second metal are in a solid solution. 
     
     
         34 . The metal alloy of any one of the preceding claims, wherein the nanocrystalline metal alloy has a first grain size and a sintered material comprising Ti in the absence of the second metal has a second grain size, the first grain size being smaller than the second grain size. 
     
     
         35 . A method of forming a nanocrystalline metal alloy, comprising:
 sintering a plurality of nanocrystalline particulates to form the nanocrystalline metal alloy;   wherein at least some of the nanocrystalline particulates comprise Ti and a second metal, and Ti is the most abundant metal by atomic percentage in at least some of the nanocrystalline particulates.   
     
     
         36 . A method of forming a nanocrystalline metal alloy, comprising:
 sintering a plurality of nanocrystalline particulates to form the nanocrystalline metal alloy; wherein:
 at least some of the nanocrystalline particulates comprise Ti and a second metal; and 
 sintering the plurality of nanocrystalline particulates involves heating the nanocrystalline particulates to a first sintering temperature that is greater than or equal to 300° C. and less than or equal to 850° C. for a sintering duration greater than or equal to 10 minutes and less than or equal to 24 hours. 
   
     
     
         37 . A method of forming a nanocrystalline metal alloy, comprising:
 sintering a plurality of nanocrystalline particulates to form the nanocrystalline metal alloy; wherein:
 at least some of the nanocrystalline particulates comprise Ti and a second metal; and 
 sintering the plurality of nanocrystalline particulates involves heating the nanocrystalline particulates such that the nanocrystalline particulates are not at a temperature of greater than or equal to 1200° C. for more than 24 hours. 
   
     
     
         38 . A method of forming a nanocrystalline metal alloy, comprising:
 sintering a plurality of nanocrystalline particulates to form the nanocrystalline metal alloy; wherein:
 at least some of the nanocrystalline particulates comprise Ti and a second metal; 
 Ti is the most abundant metal by atomic percentage in at least some of the nanocrystalline particulates; and 
 the sintering comprises heating the nanocrystalline particulates to a first sintering temperature lower than a second sintering temperature needed for sintering Ti in the absence of the second metal. 
   
     
     
         39 . A method of forming a nanocrystalline metal alloy, comprising:
 sintering a plurality of nanocrystalline particulates to form the nanocrystalline metal alloy; wherein:
 at least some of the nanocrystalline particulates comprise Ti and a second metal; and 
 the second metal and Ti exhibit a miscibility gap. 
   
     
     
         40 . A method of forming a nanocrystalline metal alloy, comprising:
 sintering a plurality of nanocrystalline particulates to form the nanocrystalline metal alloy; wherein:
 at least some of the nanocrystalline particulates comprise Ti and a second metal; 
 Ti is the most abundant metal by atomic percentage in at least some of the nanocrystalline particulates; and 
 the nanocrystalline metal alloy has a relative density of at least 80%. 
   
     
     
         41 . A method of forming a metal alloy, comprising:
 sintering powder comprising Ti and Mg to produce the metal alloy, wherein the metal alloy has a relative density of greater than or equal to 80%.   
     
     
         42 . The method of any one of  claims 35 - 41 , wherein the Ti and the second metal are present in a non-equilibrium phase. 
     
     
         43 . The method of any one of  claims 35 - 42 , wherein the non-equilibrium phase undergoes decomposition during the sintering. 
     
     
         44 . The method of any one of  claims 35 - 43 , wherein the non-equilibrium phase undergoes decomposition during the sintering, and the decomposition of the non-equilibrium phase accelerates a rate of sintering of the nanocrystalline particulates. 
     
     
         45 . The method of any one of  claims 35 - 44 , wherein the non-equilibrium phase comprises a supersaturated phase comprising the second metal dissolved in Ti. 
     
     
         46 . The method of any one of  claims 35 - 45 , wherein the second metal comprises an alkaline earth metal. 
     
     
         47 . The method of any one of  claims 35 - 46 , wherein the second metal is selected from the group consisting of Mg, La, Y, Th, Sc, Cr, Ag, Fe, Mn, Cu, and Li. 
     
     
         48 . The method of any one of  claims 35 - 47 , wherein the second metal is Mg. 
     
     
         49 . The method of any one of  claims 35 - 48 , further comprising cold pressing the plurality of nanocrystalline particulates during at least one portion of time prior to the sintering. 
     
     
         50 . The method of any one of  claims 35 - 49 , wherein the cold pressing comprises cold compression of the plurality of nanocrystalline particulates at a force greater than or equal to 300 MPa. 
     
     
         51 . The method of any one of  claims 35 - 50 , wherein the cold pressing comprises cold compression of the plurality of nanocrystalline particulates at a force greater than or equal to 300 MPa and less than or equal to 2500 MPa. 
     
     
         52 . The method of any one of  claims 35 - 51 , wherein the sintering comprises heating the nanocrystalline particulates to a first sintering temperature lower than a second sintering temperature needed for sintering Ti in the absence of the second metal. 
     
     
         53 . The method of any one of  claims 35 - 52 , wherein the sintering comprises heating the nanocrystalline particulates to a temperature greater than or equal to 300° C. and less than or equal to 850° C. for a duration greater than or equal to 10 minutes and less than or equal to 24 hours. 
     
     
         54 . The method of any one of  claims 35 - 53 , wherein the sintering comprises heating the nanocrystalline particulates to a temperature greater than or equal to 300° C. and less than or equal to 850° C. for a duration greater than or equal to 20 minutes and less than or equal to 3 hours. 
     
     
         55 . The method of any one of  claims 35 - 54 , wherein the sintering comprises heating the nanocrystalline particulates to a temperature greater than or equal to 300° C. and less than or equal to 450° C. for a duration greater than or equal to 20 minutes and less than or equal to 3 hours. 
     
     
         56 . The method of any one of  claims 35 - 55 , wherein the first sintering temperature is lower than or equal to 700° C. 
     
     
         57 . The method of any one of  claims 35 - 56 , wherein the non-equilibrium phase comprises a solid solution. 
     
     
         58 . The method of any one of  claims 35 - 57 , further comprising forming at least some of the nanocrystalline particulates by mechanically working a powder comprising Ti and the second metal. 
     
     
         59 . The method of any one of  claims 35 - 58 , further comprising forming at least some of the nanocrystalline particulates by ball milling a powder comprising Ti and the second metal. 
     
     
         60 . The method of any one of  claims 35 - 59 , wherein at least some of the nanocrystalline particulates have a grain size of smaller than or equal to 50 nm. 
     
     
         61 . The method of any one of  claims 35 - 60 , wherein at least some of the nanocrystalline particulates have a grain size of greater than or equal to 5 nm and smaller than or equal to 25 nm. 
     
     
         62 . The method of any one of  claims 35 - 61 , wherein at least some of the nanocrystalline particulates have a grain size of greater than or equal to 10 nm and smaller than or equal to 20 nm. 
     
     
         63 . The method of any one of  claims 35 - 62 , wherein the second metal is present in the nanocrystalline particulates in an amount of less than or equal to 40 atomic percent of the nanocrystalline particulates. 
     
     
         64 . The method of any one of  claims 35 - 63 , wherein the second metal is present in the nanocrystalline particulates in an amount of greater than or equal to 8 atomic percent and less than or equal to 32 atomic percent of the nanocrystalline particulates. 
     
     
         65 . The method of any one of  claims 35 - 64 , wherein the nanocrystalline metal alloy further comprises a third metal material 
     
     
         66 . The method of any one of  claims 35 - 65 , wherein the nanocrystalline metal alloy has a relative density of at least 80%, at least 85%, at least 90%, at least 95%, at least 97%, or at least 99%. 
     
     
         67 . The method of any one of  claims 35 - 66 , wherein the sintering further comprises forming a second phase at at least one of a surface and a grain boundary of the nanocrystalline particulates during the sintering; and Ti is insoluble in the second phase. 
     
     
         68 . The method of any one of  claims 35 - 67 , wherein the sintering further comprises forming a second phase at at least one of a surface and a grain boundary of the nanocrystalline particulates during the sintering; and the second phase is rich in the second metal. 
     
     
         69 . The method of any one of  claims 35 - 68 , wherein the nanocrystalline metal alloy has a first grain size and a sintered material comprising Ti in the absence of the second metal has a second grain size, the first grain size being smaller than the second grain size. 
     
     
         70 . The method of any one of  claims 35 - 69 , wherein the nanocrystalline metal alloy is substantially stable at a temperature that is greater than or equal to 100° C., at a temperature that is greater than or equal to 200° C., at a temperature that is greater than or equal to 300° C., at a temperature that is greater than or equal to 500° C., at a temperature that is greater than or equal to 600° C., and/or at a temperature that is greater than or equal to 700° C. 
     
     
         71 . The method of any one of  claims 35 - 70 , wherein the sintering is conducted essentially free of external applied stress. 
     
     
         72 . A nanocrystalline metal alloy produced by the method of any one of  claims 35 - 71 .