The mixing enthalpies of liquid Hf-Ni-Ti alloys were measured at 1873 K by applying a high-temperature isoperibolic calorimeter. The investigation was performed along the xHf/xNi = 3 section at xTi = 0-0.64 and along the xNi/xTi = 3 section at xHf = 0-0.57. The limiting partial enthalpy of mixing of undercooled liquid titanium in liquid Hf-Ni alloy is (− 92 ± 15) kJ mol−1. The partial enthalpy of mixing of undercooled liquid hafnium at infinite dilution is (− 163 ± 12) kJ mol−1. The integral mixing enthalpies are negative nearly in the entire composition range. The thermodynamic properties of liquid quaternary alloys are modelled using the associate solution model. The amorphization ranges in ternary and quaternary systems are predicted by considering a total molar fraction of associates in liquid alloys.