Bulk and surface properties of liquid Al–Cr and Cr–Ni alloys

Abstract

The energetics of mixing and structural arrangement in liquid Al-Cr and Cr-Ni alloys has been analysed through the study of surface properties (surface tension and surface segregation), dynamic properties (chemical diffusion) and microscopic functions (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter) in the framework of statistical mechanical theory in conjunction with quasi-lattice theory. The Al-Cr phase diagram exhibits the existence of different intermetallic compounds in the solid state, while that of Cr-Ni is a simple eutectic-type phase diagram at high temperatures and includes the low-temperature peritectoid reaction in the range near a CrNi(2) composition. Accordingly, the mixing behaviour in Al-Cr and Cr-Ni alloy melts was studied using the complex formation model in the weak interaction approximation and by postulating Al(8)Cr(5) and CrNi(2) chemical complexes, respectively, as energetically favoured.

Thermophysical Properties of Advanced Ni‐Based Superalloys in the Liquid State Measured on Board the International Space Station

“…From the obtained surface tension data in this and other studies, such as in refs. [26,51] the compound formation model by Novakovic and co-workers [51,56] predicts the surface tension of Ni-based superalloys satisfyingly well. The viscosity predictions by the equation of Mills et al [53] only explain the viscosity of CMSX-10 (however, not precisely), but cannot predict the viscosity of LEK94 and MC2.…”

Thermophysical properties of some Ni-based superalloys in the liquid state relevant for solidification processing

“…The surface tension of liquid Al-Ni alloys has been investigated by the ideal or perfect solution model, by the QCA for the regular solution [32,33], and by the CFM [5,34], given by Eqs. (1-3), as follows…”

“…In particular, the Toop model is asymmetric one and it is [32,34] were combined into the Toop model. The same model was used to predict the surface tension of Al-Cr-Ni ternary alloys using as input the surface tensions of its binary subsystems calculated by the CFM [5,33]. Full details of the mathematical formalism of the geometric models are reported in [5,36] …”

Evaluation Model for Viscosity of Fe–Ni–Cr Alloys Using Gibbs Free Energy of Mixing and Geometric Methods

“…1 and listed in Table 2. As for the Ni-Cr system, data concerning its mixing Gibbs energy studied by Novakovic et al 32) can reproduce the experimental values fairly well by enabling a more precise classification of the Ni-Cr system in terms of weakly compound-forming alloys. The mixing Gibbs energies of Ni-Cr alloys are also shown in Fig.…”