Element and Phase Composition, Mechanical Properties of Titanium Surface Layer Alloyed by Zr, Nb, Al Under the Action of Compression Plasma Flows

Abstract

In this work, the element and phase compositions and mechanical properties of a titanium (Ti) surface layer alloyed by zirconium (Zr), niobium (Nb), and aluminum (Al) under the impact of compression plasma flows on an Nb–Ti–Zr–Al/Ti substrate coating system were investigated. X-ray diffraction analysis, scanning electron microscopy, energy-dispersive microanalysis, microhardness measurements, and tribological tests were used as investigation techniques. The findings showed that the plasma impact resulted in dissolution of the coating and formation of a Ti surface layer with a thickness of ~ 10 μm alloyed by Zr, Nb, and Al atoms. The increase in the energy absorbed by the surface layer resulted in a decrease in the concentration of the alloyed elements. Solid solutions based on the α-Ti and martensite α-Ti phases were observed in the alloyed layer. Surface titanium nitride formed after the plasma impact due to the usage of nitrogen as a plasma generating gas. Alloying by plasma impact led to an increase in the microhardness and a decrease in the friction coefficient.