Hard metal materials

Abstract

A hard metal material and a method of manufacturing a component of the hard metal material are disclosed. The hard metal material comprises 5-50 volume % particles of a refractory material dispersed in a host metal. The method comprises forming a slurry of 5-50 volume % particles of the refractory material dispersed in a liquid host metal in an liquid atmosphere and pouring the slurry into a mould and forming a casting of the component.

1 . A hard metal material comprising 5-50 volume % particles of a refractory material dispersed in a host metal, wherein the refractory material comprises particles of carbides and/or nitrides and/or borides of any one or more than one of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, and molybdenum. 
     
     
         2 . The hard metal material defined in  claim 1  wherein the particles of the refractory material also comprise tungsten. 
     
     
         3 . The hard metal material defined in  claim 1  comprises 5-40 volume % particles of the refractory material dispersed in the host metal. 
     
     
         4 . The hard metal material defined in  claim 1  comprises greater than 10 volume % particles of the refractory material dispersed in the host metal. 
     
     
         5 . The hard metal material defined in  claim 1  comprises less than 30 volume % particles of the refractory material dispersed in the host metal. 
     
     
         6 . The hard metal material defined in  claim 1  wherein the host metal comprises a ferrous alloy, a stainless steel, an austenitic-manganese steel, or an iron-based or a nickel-based or a cobalt-based superalloy. 
     
     
         7 . A method of manufacturing a component of a hard metal material comprising:
 (a) forming a slurry of a hard metal material comprising 5-50 volume % particles of a refractory material dispersed in a liquid host metal in an inert atmosphere, and   (b) pouring the slurry into a mould and forming a casting of the component in an inert atmosphere.   
     
     
         8 . The method defined in  claim 7  comprises forming the slurry and thereafter forming the casting of the component in a chamber under vacuum conditions which remove air from the chamber and supplying an inert gas into the chamber. 
     
     
         9 . The method defined in  claim 7  wherein the refractory material is less than 400 microns particle size. 
     
     
         10 . The method defined in  claim 7  comprises selecting the refractory material to have a smaller thermal contraction than the host metal. 
     
     
         11 . The method defined in  claim 7  comprises selecting the density of the refractory material, compared to the density of the host metal in the liquid state to control the dispersion of the particles of the refractory material in the host metal. 
     
     
         12 . A method of forming a wear resistant hard metal material, the method comprising adding (a) niobium or (b) niobium and titanium to a melt containing a host metal in a form that produces particles of niobium carbide and/or particles of a chemical mixture of niobium carbide and titanium carbide in a range of 10 to 40 wt % of the total weight of the hard metal material in a microstructure of a solidified metal alloy, and allowing the melt to solidify to form the solid hard metal material. 
     
     
         13 . The method as defined in  claim 12  wherein the particles of niobium/titanium carbides have a general formula (Nb x ,Ti y )C. 
     
     
         14 . The method as defined in  claim 12  comprising forming a slurry of particles of niobium carbide and/or niobium/titanium carbides suspended in the melt and allowing the melt to solidify to form the solidified hard metal material. 
     
     
         15 . A method of casting a hard metal material having a dispersion of a chemical mixture of niobium carbides and titanium carbides in a host metal which forms a matrix of the hard metal material, the method comprising selecting the density of the niobium/titanium particles in relation to the density of the host metal and therefore selectively controlling the dispersion of the niobium/titanium particles in the matrix ranging from a uniform dispersion to a non-uniform dispersion. 
     
     
         16 . A casting of the metal alloy made by the method defined in  claim 15 . 
     
     
         17 . The casting defined in  claim 16  wherein the metal alloy is a ferrous alloy, a stainless steel or an austenitic manganese steel. 
     
     
         18 . A method of forming a hard metal material comprising:
 (a) forming a slurry of a hard metal material comprising 5-50 volume % particles of a refractory material dispersed in a liquid host metal, and   (b) allowing the slurry to solidify to form a solid hard metal material.   
     
     
         19 . A method of forming a wear resistant hard metal material, the method comprising adding any one or more of the nine transition metals titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten to a melt of a host metal in a form that produces particles of carbides and/or nitrides and/or borides of any one or more of the nine transition metals in a range of 5 to 50 volume % of the total volume of the hard metal material, and allowing the melt to solidify to form the solid hard metal material. 
     
     
         20 . A method of casting a hard metal material having a dispersion of refractory material particles of carbides and/or nitrides and/or borides of any one or more of the nine transition metals titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten in a host metal which forms a matrix of the hard metal material in a solid casting, the method comprising selecting the density of the refractory material particles in relation to the density of the host metal and therefore selectively controlling the dispersion of the refractory material particles in the matrix of a solid casting ranging from a uniform dispersion to a non-uniform dispersion. 
     
     
         21 . A method of forming a wear resistant hard metal material, the method comprising adding niobium, ferro-niobium, or ferro-niobium-titanium to a melt of a ferrous alloy comprising carbon and thereby forming particles of niobium carbide and/or niobium-titanium carbide; and allowing the melt to solidify to form the solid hard metal material, wherein the particles of niobium carbide and/or niobium-titanium carbide are present in a range of 10 to 40 wt. % of the total weight of the hard metal material.