MODIFICATION OF ZrN/Ti-6Al-4V SYSTEM STRUCTURE BY COMPRESSION PLASMA FLOWS TREATMENT

Abstract

Investigation of compression plasma flows impact on structure, phase, and elemental composition, as well as mechanical properties of Ti-6Al-4V titanium alloy with ZrN coating was carried out in this work. X-ray diffraction, scanning electron microscopy, energy dispersion X-ray analysis, samples weight measurements, microhardness and tribological tests were used as investigation techniques. The findings showed that plasma impact led to the formation of a composite surface layer based on titanium alloy containing inclusions of undissolved ZrN coating. Growth of the absorbed energy density resulted in a decrease of zirconium and nitrogen concentration in the surface layer due to erosion. Formation of solid solutions on the basis of α-Ti and β-Ti was found in the layer analyzed by X-ray diffraction. Presence of nitrogen in a vacuum chamber as plasma generating gas led to the formation of TiN on the surface. Plasma impact resulted in decrease of ZrN/Ti-6Al-4V system microhardness and decrease of friction coefficient (at specific treatment regimes).