No 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.

The mechanism of the wear of a composite ceramic coating, which has been produced on the D16 aluminum-based alloy using microarc oxidation, under low-amplitude reciprocal friction (fretting) is studied. The ball-on-plane arrangement in which a diamond ball slides reciprocally against a flat specimen covered with the microarc-oxidation coating is considered. The three following regions of the fracture of the coating have been identified: the moderate wear range, which is characterized by a constant wear rate and in which a smoothed wear spot is formed; the severe wear range, which is characterized by the partial delamination of the top layer of the coating; and the extreme wear range, which is characterized by the cracking of the coating through its entire thickness up to the metal. Based on the experimental results, the boundary of the transition to the inoperative region of the extreme wear of the coating has been determined over the entire ranges of the load and displacement under study.

No abstract

No abstract