Influence of ion implantation on nanoscale intermetallic-phase formation in Ti–Al, Ni–Al and Ni–Ti systems

The objective of this investigation was to study the chemical and phase composition, structure and mechanical properties of titanium and nickel surface layers modified by high-intensity ion implantation with the use of a “Raduga-5”-vacuum-arc ion beam and plasma flow source. Ti samples were irradiated with Al ions, and Ni targets were implanted with Al or Ti ions. It was established that ion implantation in high-intensity mode allows the formation of finely-dispersed (grain size less than 100 nm) intermetallic phases A3B and AB (A = Ti, Ni; B = Al, Ti), as well as solid solutions of composition variable in depth in the surface layer. The localization regions of the intermetallic phases formed over the implanted layer depth were determined. Increasing dose of irradiated ions leads to an increase in the thickness of the ion-alloyed layers up to 3 μm and in the mean size of intermetallic-phase grains. It was shown that high-intensity ion implantation results in a considerable increase of microhardness and wear resistance of the materials. The inference is that the structural and phase state of the ion-alloyed layers affects their mechanical properties.