Compositional Glass: A State with Inherent Chemical Disorder, Exemplified by Ti-rich Ni3(Al,Ti)1 D024 Phase

A compositional glass is a state with an unavoidable disorder in chemical compositions on each site, characterized by frustration and freezing of the degrees freedom at low temperature. From this full atomic long-range order unachievable reasonable thermodynamic treatment. There similarity between spin (a magnetic orientations) (with site occupations elements): both have frustrated ground states frozen temperatures T < Tf (here called temperature). While it possible to perform ground-state search glass, resulting set fully ordered structures does not adequately represent real solid inherent disorder. Compositional glasses constitute class materials, which insufficiently understood, but high industrial importance. Some phases precipitated alloys (including steels, high-entropy alloys, superalloys) might be glasses, their better understanding would facilitate materials design. Due strength operating temperatures, superalloys are used combustion engines particularly jet turbine engines. Precipitation strengthening nickel area active research. Local phase transformations inside Ni3Al-based precipitates particular interest due impact creep strength. In Ni3(Al1−xTix)1 ternary system, competing Ni3Al-type L12 (γʹ) Ni3Ti-type D024 (η), while D019 (χ) higher energy. These three differ stacking layers: locally, last two look like internal external faults L12. We compute enthalpies disordered structures, examine stability, investigate predict that Ti-rich Al/Ti sublattice. To resolve apparent contradictions among previous experiments confirm our prediction, we X-ray diffraction scanning electron microscopy analysis cast Ni3(Ti0.917Al0.083)1 sample. Our measurements appear ab initio computed results. results elucidate properties provide precipitation mechanisms Ni superalloys.