High Melting Point Metal Based Alloy Material Lexhibiting High Strength and High Recrystallization Temperature and Method for Production Thereof

Abstract

A refractory metal-based alloy material exhibiting high strength and high recrystallization temperature includes a worked material obtained by carburizing, while using a carbon source and coexisted oxygen, a material containing nitride particles of a solute metal dispersed and precipitated in a matrix by multi-step nitriding of a worked alloy material containing one metal selected from Mo, W, and Cr as a matrix and at least one element selected from Ti, Zr, Hf, V, Nb, and Ta as the solute metal, wherein the worked material contains carbon segregated at grain boundaries as a result of the carburizing and oxide particles converted from the nitride particles.

1 . A refractory metal-based alloy material exhibiting high strength and high recrystallization temperature, comprising a worked material obtained by carburizing, while using a carbon source and coexisted oxygen, a material containing nitride particles of a solute metal dispersed and precipitated in a matrix by multi-step nitriding of a worked alloy material containing one metal selected from Mo, W, and Cr as a matrix and at least one element selected from Ti, Zr, Hf, V, Nb, and Ta as the solute metal, wherein as a result of the carburizing, the worked material contains carbon segregated at grain boundaries and oxide particles converted from the nitride particles.  
   
   
       2 . The refractory metal-based alloy material exhibiting high strength and high recrystallization temperature according to  claim 1 , wherein a worked structure is maintained in the surface of the alloy material, and the interior of the alloy material includes a recrystallized structure.  
   
   
       3 . The refractory metal-based alloy material exhibiting high strength and high recrystallization temperature according to  claim 1 , wherein the matrix is Mo, the solute metal is Ti, and the recrystallization temperature is 1,600° C. or more.  
   
   
       4 . A process of producing the refractory metal-based alloy material exhibiting high strength and high recrystallization temperature according to  claim 1 , comprising subjecting a worked alloy material containing one metal selected from Mo, W, and Cr as a matrix and at least one element selected from Ti, Zr, Hf, V, Nb, and Ta as a solute metal to multi-step internal nitriding so that nitride particles of the solute metal are dispersed in the matrix, and then carburizing the resulting worked alloy material by using a carbon source and coexisted oxygen.  
   
   
       5 . The process of producing the refractory metal-based alloy material according to  claim 4 , wherein a first nitriding step is conducted at a temperature not more than a recrystallization upper limit temperature of the worked alloy material but not less than a temperature 200° C. lower than a recrystallization lower limit temperature so as to produce and diffuse nitride particles of the solute metal, and then a second nitriding step is conducted at a temperature not less than a recrystallization lower limit temperature of the resulting worked alloy material after the first step nitriding so as to allow the nitride particles produced and dispersed in the first nitriding step to grow into grains and be stabilized.  
   
   
       6 . The process of producing the refractory metal-based alloy material according to  claim 4 , wherein the carburizing is conducted by using inert gas containing 0.1 to 5 percent by volume of CO.