Microstructure, fatigue strength and erosion resistance of MAX-phase embedded Ti-Si-B nanostructured coatings on Ti-6Al-4V

Abstract

Ti-Si-B nanostructured coatings were deposited on Ti-6Al-4V substrates by vacuum plasma processing with droplet separation. A composite Ti-Si-B cathode fabricated by self-propagating high temperature synthesis with subsequent hot pressing was used. The microstructure and mechanical properties of the obtained coatings were analysed by applying Auger-electron spectroscopy, X-ray diffraction and scanning electron microscopy methods accompanied by hardness measurements, fatigue strength and erosion resistance testing. It was established that Ti-Si-B nanostructured coating deposition leads to significant improvement of fatigue strength and erosion resistance of Ti-6Al-4V. A noticeable raise of the fatigue strength is attributed to presence of low dispersed Ti3SiB2 MAX-phase inclusions that suppress fatigue crack propagation.

High-current pulsed electron beams for modification of the surface layer of parts of the flow part of a modern gas turbine engine

“…The blades came out of service with a damaged coating and are subject to repair in accordance with the regulatory documentation. Based on the previously obtained results of the study, irradiation modes were established [1][2][3].…”

“…Moreover, the values of the endurance limit on the established test base and the thickness of the gas-saturated layer formed during the tests are determined by the state of the surface layers of the operated parts, namely: the presence of macro-and micro-defects, surface roughness, heterogeneity of chemical and phase composition of compositions, heterogeneity of the distribution of linear and point defects, the concentration of these defects, increased degree of hardening etc. Since with any kind of corrosion of erosive and fatigue loading, the maximum loads develop directly on the surface, it is in the nearsurface layers that fatigue cracks originate and the initial stage of their growth occurs by various mechanisms [1][2][3]. This implies one of the basic principles of the development of new technological processes aimed at increasing fatigue strength, heat resistance, erosion and corrosion resistance of any part -surface modification, leading to the formation of coatings unique in properties, residual compressive stresses and increasing the uniformity of the physico-chemical state of the material in the surface layer.…”

“…This implies one of the basic principles of the development of new technological processes aimed at increasing fatigue strength, heat resistance, erosion and corrosion resistance of any part -surface modification, leading to the formation of coatings unique in properties, residual compressive stresses and increasing the uniformity of the physico-chemical state of the material in the surface layer. Since pulsed electron beam processing makes it possible to radically change the chemical and phase compositions, as well as the structure of the material in surface layers with a thickness of several tens and hundreds of nanometers to 10-100 microns, it is natural to assume that this type of processing, implemented at the atomic level, is one of the most promising methods for improving the performance of parts of a wide range [3,4].…”

Formation of residual stresses in the surface layers of corrosion-resistant steel samples after irradiation with high-current pulsed electron beams

“…The influence of high-current electron beams in previous works [1][2][3] on the roughness, topography, and modification of the surface layers of parts obtained by traditional methods was analyzed, taking into account the issues of post-processing and the formation of residual stresses in the surface layers of parts obtained by SLM methods. After that, it was proposed to irradiate using radiation technologies as a tool for post-processing parts obtained by additive technologies from various metallic materials.…”