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.

1 - 72 . (canceled) 
     
     
         73 . 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; and   wherein for at least 20% of the time during which sintering is performed, the maximum external pressure applied to the nanocrystalline particulates is less than or equal to 2 MPa.   
     
     
         74 . The method of  claim 73 , wherein the nanocrystalline metal alloy has a relative density of at least 80%. 
     
     
         75 . The method of  claim 73 , wherein the nanocrystalline metal alloy has a relative density of at least 98%. 
     
     
         76 . The method of  claim 75 , wherein the nanocrystalline metal alloy is a bulk nanocrystalline metal alloy. 
     
     
         77 . The method of  claim 76 , wherein the bulk nanocrystalline metal alloy has an average grain size of less than 300 nm. 
     
     
         78 . The method of  claim 77 , wherein the second metal is selected from the group consisting of Mg, La, Y, Th, Sc, Cr, Ag, Fe, Mn, Cu, and Li. 
     
     
         79 . The method of  claim 78 , wherein the second metal is Mg. 
     
     
         80 . The method of  claim 73 , wherein the Ti and the second metal are present in a non-equilibrium phase. 
     
     
         81 . The method of  claim 80 , wherein the non-equilibrium phase comprises a solid solution. 
     
     
         82 . The method of  claim 80 , wherein the non-equilibrium phase undergoes decomposition during the sintering. 
     
     
         83 . The method of  claim 82 , wherein the decomposition of the non-equilibrium phase accelerates a rate of sintering of the nanocrystalline particulates. 
     
     
         84 . The method of  claim 80 , wherein the non-equilibrium phase comprises a supersaturated phase comprising the second metal dissolved in Ti. 
     
     
         85 . The method of  claim 73 , further comprising forming at least some of the nanocrystalline particulates by mechanically working a powder comprising Ti and the second metal. 
     
     
         86 . The method of  claim 73 , wherein the second metal is selected from the group consisting of Mg, La, Y, Th, Sc, Cr, Ag, Fe, Mn, Cu, and Li. 
     
     
         87 . The method of  claim 73 , wherein the second metal is Mg. 
     
     
         88 . The method of  claim 73 , wherein 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. 
     
     
         89 . The method of  claim 73 , further comprising cold pressing the plurality of nanocrystalline particulates during at least one portion of time prior to the sintering. 
     
     
         90 . The method of  claim 89 , 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. 
     
     
         91 . The method of  claim 73 , 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. 
     
     
         92 . The method of  claim 73 , 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.