Alloys-by-design: Role of atomic properties on the phase equilibria of CuAlMn-based alloys

The Hume-Rothery rules are used to predict a solid-solution formation in metallic alloys. However, the parameters that guide the interactions in precipitated phases are unclear. In complex systems, such as CuAlMn-based alloys, these new phases are quite important owing to the effects on the system properties. In this study, the addition of alloying elements in Cu74.5Al15.0Mn10.5 on the atomic and electronic properties were used as para- meters for a qualitative prediction of the phase equilibria. Herein, Cu74.5Al15.0Mn10.5 X (1.6) (X is an element of [Ag; Be; Co; Ga; Gd; Sb; Zr]) alloys were characterised using differential scanning calorimetry, optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and magnetisation measurements as a function of the applied field. The results showed that Be and Ga additions did not induce a new phase formation, whereas Ag, Co, Gd, Sb, and Zr additions promoted the production of intermetallic compounds and a new solid-solution. The formation of new phases and the equilibrium perturbance showed a strong dependence on the atomic properties and the electronic configuration of the fourth added element. Consequently, the magnetic properties were affected as a function of the fourth element addition.