High-temperature resistant alloy with low contents of cobalt and nickel

Abstract

High-temperature resistant alloys, with low Co and Ni contents and a predominant face-centered cubic (FCC) matrix, are formed by selecting an appropriate combination of elements based on a ‘multi-principle-element alloy design’. It exhibits excellent properties in terms of workability, toughness, high-temperature strength, corrosion resistance and oxidation resistance. These alloys are designed to incorporate five to seven principal elements, which include Co, Cr, Fe, and Ni, plus one, or a combination of Al, Mo, and Ti. The Co and Ni elements have contents of 20 to 35 atomic percent, and those of Cr and Fe are between 12.5 and 20 atomic percent. The sum of the Co, Ni, Cr, and Fe is not less than 65 atomic percent, and the sum of Al, Mo, and Ti contents is between 5 and 25 atomic percent. The properties of the alloys can be further modified by the addition of minor elements, such as Ag, B, C, Cu, Mn, Nb, Ta, Si, V, W, Y, and Zr, whose sum does not exceed 10 atomic percent.

1 . A novel high-temperature resistant multi-principal-element alloy, with low cobalt and nickel contents, being described by the following chemical formula:
   (Co, Cr, Fe, Ni) x M y N z , for which:   x≧65 atomic percentage, wherein the elemental contents of Co and Ni are each 20 to 35 atomic percent, and the elemental contents of Cr and Fe are each 12.5 to 20 atomic percent;   5≦y≦25 atomic percent, wherein M is one, or a combination of Al, Mo, and Ti; and   0<z≦10 atomic percent, wherein N is one, or a combination of Ag, B, C, Cu, Mn, Nb, Ta, Si, V, W, Y, and Zr.   wherein the hardness of the alloy increases with increasing thickness reduction of the alloy caused by working on the alloy, and the hardness of the alloy increases as the alloy is age hardened at a temperature over 400° C.   
   
   
       2 . The novel high-temperature resistant alloy, with low contents of cobalt and nickel, as described in  claim 1 , wherein the alloy is cast by vacuum arc melting. 
   
   
       3 . The novel high-temperature resistant alloy, with low contents of cobalt and nickel, as described in  claim 1  or  2 , wherein the alloy possesses a predominant face-centered cubic matrix. 
   
   
       4 . The novel high-temperature resistant alloy, with low contents of cobalt and nickel, as described in  claim 1  or  2 , wherein the alloy is worked by forging. 
   
   
       5 . The novel high-temperature resistant alloy, with low contents of cobalt and nickel, as described in  claim 1  or  2 , wherein the alloy is processed by thermal homogenization. 
   
   
       6 . The novel high-temperature resistant alloy, with low contents of cobalt and nickel, as described in  claim 1  or  2 , wherein the alloy is worked by rolling. 
   
   
       7 . The novel high-temperature resistant alloy, with low contents of cobalt and nickel, as described in  claim 1  or  2 , wherein the alloy is processed by aging hardening.