科研之友
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摘要
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),B1-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.
- 出版日期2017-1-1
