Formation of Nanosized Intermetallic Phases upon High-Intensity Implantation of Aluminum Ions into Titanium

Abstract

The chemical and phase compositions, the structure, and the mechanical and tribological properties of titanium surface layers modified by high-intensity aluminum ion implantation with the use of a Raduga-5 vacuum-arc ion beam and plasma flow source are investigated. Ion-alloyed titanium surface layers that contain finely dispersed discrete intermetallic phases TiAl and Ti3Al, as well as a solid solution of aluminum in titanium, are produced. An increase in the dose of implanted ions from 2.2 × 1017 to 2.2 × 1018 ions/cm2 leads to an increase in the thickness of the ion-alloyed titanium layer (from 0.4 to 2.6 µm) and in the mean sizes of intermetallic-phase grains (from 20 to 70 nm) and their conglomerates (from 71 to 584 nm). It is shown that the implantation of aluminum ions into titanium results in a considerable increase in the microhardness and the wear resistance of the materials. The maximum microhardness is observed for the titanium sample implanted with aluminum ions at an irradiation dose of 2.2 × 1018 ions/cm2. The inference is made that the structure and phase composition of the ion-alloyed titanium layers affect their mechanical and tribological properties.