  In 2006, a novel cobalt-based superalloy was discovered [1] with mechanical
properties better than some conventional nickel-based superalloys. As with
conventional superalloys, its high performance arises from the
precipitate-hardening effect of a coherent L1$_2$ phase, which is in two-phase
equilibrium with the fcc matrix. Inspired by this unexpected discovery of an
L1$_2$ ternary phase, we performed a first-principles search through 2224
ternary metallic systems for analogous precipitate-hardening phases of the form
$X_{3}$[$A_{0.5}, B_{0.5}$], where $X$ = Ni, Co, or Fe, and [$A,B$] = Li, Be,
Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn Ga, Sr, Y, Zr, Nb, Mo,
Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, or Tl.
We found 102 systems that have a smaller decomposition energy and a lower
formation enthalpy than the Co$_{3}$(Al, W) superalloy. They have a stable
two-phase equilibrium with the host matrix within the concentration range
$0<x<1$ ($X_{3}$[$A_{x}, B_{1-x}$]) and have a relative lattice mismatch with
the host matrix of less than or equal to 5%. These new candidates, narrowed
from 2224 systems, suggest possible experimental exploration for identifying
new superalloys. Of these 102 systems, 37 are new; they have no reported phase
diagrams in standard databases. Based on cost, experimental difficulty, and
toxicity, we limit these 37 to a shorter list of six promising candidates of
immediate interest. Our calculations are consistent with current experimental
literature where data exists.
