Influence of chemical composition of initial powders on structure and properties of Ti-Ta-Zr coatings fabricated on cp-titanium substrates by electron beam cladding

Abstract

In this study Ti-Ta-Zr corrosion resistant coatings fabricated by electron beam treatment of Ti substrates were investigated. The series of experiments on varying Ta and Zr concentrations in initial powder mixtures aimed on identifying influence of the alloying components ratio on structure and properties of coatings were carried out. It was found that during the electron beam cladding the high-quality coatings with a dendritic structure exhibited uneven distribution of alloying components in a cross section were formed. Moreover scanning electron microscopy (SEM) revealed the formation of needlelike structure. However difference in Ta and Zr concentrations in initial powder mixtures did not cause significant structural transformations in the coatings. Meanwhile the direct dependence between microhardness of the surface layers and Zr content in it was revealed. The maximal microhardness level was detected in the coating containing 60 % Zr. The impact strength test indicated decrease of impact toughness of titanium samples after cladding by a factor of 1.5...2.