Design and characterization of TiZrNb-M (M = Fe, Co, Ni) eutectic multi-component alloys

Designing eutectic multi-component alloys for advanced engineering applications requires efficient strategies, particularly for systems lacking reliable thermodynamic data. In this work, a methodology by combing qualitative-assessment and quantitative-calculation is proposed to efficiently obtain eutectic compositions within TiZrNb-M (M = Fe, Co, Ni) quaternary systems. Firstly, six eutectic compositions were obtained based on theoretical calculation for TiZrNb-M systems. It was then verified by experiments that five out of the six calculated alloys exhibit either eutectic structures or near-eutectic structures, achieving an accuracy rate of 83 %. After slight experimental adjustments, five novel eutectic alloys (Ti_24.00Z_r21.70Nb_12.10Ni_42.20, Ti_5.64Zr_5.78Nb_5.78Ni_82.80, Ti_26.33Zr_19.02Nb_24.35Fe_30.30, Ti_6.33Zr_1.95Nb_4.02Fe_87.7 and Ti_8.25Zr_2.20Nb_5.27Co_84.28) were obtained. Comprehensive microstructural characterization, including phase analysis and morphological examination, confirmed the presence of eutectic structures and provided insights into phase stability and solidification behavior. Moreover, a comparative discussion with CALPHAD-based methods highlights the advantages of the proposed methodology in systems where conventional thermodynamic databases are incomplete or unreliable. The findings not only provide novel refractory eutectic multi-component alloys, but also demonstrate a framework for eutectic multi-component alloys design, complementing existing computational tools and enabling the discovery of eutectic alloys in complex alloy systems.