Effect of Titanium Content and Mechanical Alloying Time on the Formation of Nanocrystalline Solid Solutions in the Ni–Al–Ti System

This work investigates the effect of titanium content and the duration of mechanical alloying on the structural and phase state of powder mixtures in the Ni–Al–Ti system. The initial mixtures of Ni68Al25Ti7, Ni72Al22Ti6, Ni70Al21Ti9, and Ni75Al25 were subjected to high-energy milling in a planetary ball mill for 1–6 h. It was found that the addition of titanium accelerates the dissolution of components and promotes the formation of a supersaturated fcc Ni(Al,Ti) solid solution. The most pronounced effects were observed for the Ni70Al21Ti9 composition, where after 6 h of alloying, the minimum crystallite size (11.3 nm) and maximum lattice strain (1.52%) were achieved. It is shown that titanium reduces the tendency for cold welding and promotes more uniform particle refinement. The optimal conditions for synthesizing a nanocrystalline solid solution with a homogeneous structure are a titanium content of 9 at.% and a mechanical alloying duration of 6 h. The resulting powders are promising for subsequent sintering and application in structural and heat-resistant intermetallic alloys and coatings.