Al-Ti-based alloys are of enormous technical relevance due to their specific properties. For studies in atomic dynamics, surface physics and industrial processing the precise knowledge of the thermophysical properties of the liquid phase is crucial. In the present work, we systematically measure mass density, ρ (g cm−3), and the surface tension, γ (N m−1), as functions of temperature, T, and compositions of binary Al-Ti melts. Electromagnetic levitation in combination with the optical dilatometry method is used for density measurements and the oscillating drop method for surface tension measurements. It is found that, for all compositions, density and surface tension increase linearly upon decreasing temperature in the liquid phase. Within the Al-Ti system, we find the largest values for pure titanium and the smallest for pure aluminum, which amount to ρ(L,Ti) = 4.12 ± 0.04 g cm−3 and γ(L,Ti) = 1.56 ± 0.02 N m−1; and ρ(L,Al) = 2.09 ± 0.01 g cm−3 and γ(L,Al) = 0.87 ± 0.06 N m−1, respectively. The data are analyzed concerning the temperature coefficients, ρT and γT, excess molar volume, VE, excess surface tension, γE, and surface segregation of the surface active component, Al. The results are compared with thermodynamic models. Generally, it is found that Al-Ti is a highly nonideal system.
