Precipitation strengthened high-entropy superalloy

Abstract

The present invention discloses a new alloy design of precipitation strengthened high entropy superalloy (HESA), which is composed of at least one principal element, a plurality of base element, and at least one precipitation strengthening element for controlling the elemental segregation between the high-entropy matrix and ordered precipitate. Through the addition of the precipitation strengthening element, while substituting the same amount of the principle element, not only the ordering energy and the volume fraction of strengthening precipitates, but also the mechanical strength of the alloy can be apparently elevated. Therefore, this newly-developed precipitation strengthened HESA can further improve the thermal capability and mechanical properties from the previously proposed high-entropy alloys.

What the claim is: 
     
         1 . The precipitation strengthened high-entropy superalloy, comprising:
 at least one principal element with a first element content of at least 35 at %, being a siderophile element;   a plurality of base elements for forming a high-entropy matrix with the principal element, wherein each of the base elements has a second element content of at least 5 at %; and   at least one precipitation strengthening element with a third element content of at least 0.1 at %, for forming an ordered precipitate with the principal element and/or the base elements;   wherein the high-entropy matrix and ordered precipitate have a first volume fraction and a second volume fraction, respectively; and the thermal stability of the precipitation strengthened high-entropy superalloy would be enhanced through simultaneously increasing the third element content and decreasing the first element content by an element segregating amount.   
     
     
         2 . The precipitation strengthened high-entropy superalloy of  claim 1 , wherein the first volume fraction is in a range from 20% to 90%, while the second volume fraction of ordered precipitate is in a range between 10% and 80%. 
     
     
         3 . The precipitation strengthened high-entropy superalloy of  claim 1 , wherein the high-entropy matrix has a first mixing entropy value equal to or greater than 1.5R, and the ordered precipitate has a second mixing entropy value less than the first mixing entropy value. 
     
     
         4 . The precipitation strengthened high-entropy superalloy of  claim 1 , wherein the element segregating amount is at least 0.5 at %; moreover, the second mixing entropy value would be lowered after increasing the third element content by substituting the element segregating amount of the first element content of the principal element. 
     
     
         5 . The precipitation strengthened high-entropy superalloy of  claim 1 , wherein the siderophile element is selected from the group consisting of Nickel (Ni), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co) and Platinum group element (PGE). 
     
     
         6 . The precipitation strengthened high-entropy superalloy of  claim 1 , wherein both the base element and the strengthening element are selected from the group consisting of Aluminum (Al), Titanium (Ti), Tantalum (Ta), Niobium (Nb), Chromium (Cr), Manganese (Mn), Vanadium (V), and combination of the aforesaid two or more elements. 
     
     
         7 . The precipitation strengthened high-entropy superalloy of  claim 1 , further comprising at least one precious metal element with a fourth element content less than 15 wt %. 
     
     
         8 . The precipitation strengthened high-entropy superalloy of  claim 7 , wherein the precious metal element is selected from the group consisting of Tantalum (Ta), Molybdenum (Mo), Tungsten (W), Rhenium (Re), Ruthenium (Ru), Silver (Ag) and combination of the aforesaid two or more elements. 
     
     
         9 . The precipitation strengthened high-entropy superalloy of  claim 7 , further comprising at least one grain boundary strengthening element with a fifth element content less than 15 wt %. 
     
     
         10 . The precipitation strengthened high-entropy superalloy of  claim 9 , wherein the grain boundary strengthening element is selected from the group consisting of Carbon (C), Silicon (Si), Boron (B), Beryllium (Be), Magnesium (Mg), Calcium (Ca), Hafnium (Hf), rare earth element and combination of the aforesaid two or more elements.