Figure 5.

Al-Co-Ni-Ti system: (a) Unfolded tetrahedral quaternary phase diagram showing the four isothermal sections of the ternary subsystems calculated at 800°C (FAT = 3/4), highlighting the single-phase fields. In addition to the solid solution phases, the quaternary system includes several ordered solid solutions (L1₂, B2), binary intermetallics (Al₅Co₂, Al₃Co, Al₁₃Co₄, Al₉Co₂, Al₃Ni, Al₃Ni₂, BCT, Al₂Ti, AlTi, AlTi₃, Ni₃Ti, NiTi₂, Laves-C15 and Laves-C16) and several ternary intermetallics (H_L2₁, Laves_C14). (b) Difference (appearing in white) between the extent of the various phase fields calculated for FAT = 3/4 and FAT = 0 (the case when all ternary intermetallics are suspended, see Figure 3). Parallel coordinate plots showing the predicted range of existence (4D compositional coordinates) of the bcc phase in the quaternary Al-Co-Ni-Ti phase diagram at 800 °C for (c) FAT = 3/4 and (d) FAT = 0.