Mechanosynthesis of Ni-Al-Ti intermetallic compounds: influence of milling time and titanium content

Abstract

The synthesis of intermetallic compounds in Ni-Al systems is of significant interest due to their potential applications in high-temperature materials. This study aims to investigate the effect of milling time and titanium addition on phase formation, particle size evolution, and microstructural development in Ni-Al and Ni-Al-Ti powder mixtures with different compositions. Mechanical alloying was carried out in a planetary ball mill for up to 6 hours, and the resulting powders were analyzed using X-ray diffraction and scanning electron microscopy. The results show that the particle size evolution follows a non-monotonic behavior, characterized by initial agglomeration during the early stage of milling, followed by fragmentation and subsequent stabilization. After 3 hours of processing, solid solutions based on nickel are formed due to the dissolution of aluminum and titanium in the crystal lattice. Further milling up to 6 hours leads to the formation of intermetallic phases with a disordered structure. The addition of titanium accelerates phase transformations and promotes structural refinement, with the most pronounced effect observed for compositions with higher titanium content. The findings demonstrate that mechanical alloying is an effective method for producing refined intermetallic structures, with optimal processing conditions in the range of 3 to 6 hours of milling.