PSI - Issue 65

E.G. Zemtsova et al. / Procedia Structural Integrity 65 (2024) 310–316

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E.G. Zemtsova et al. / Structural Integrity Procedia 00 (2024) 000–000

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composite, a high temperature (1100 °C) was used. High temperatures contribute to the chemical reaction between carbides and the metal matrix, and undesired nickel carbide can be obtained, which embrittles the system, reduces the strength characteristics of the samples and significantly reduces the composite plasticity. However, X-ray phase analysis shows the absence of a nickel carbide phase. Instead, the Ni2Al3 phase was identified (Table 1), which presence up to 6% can lead to additional hardening of Ni composites.

Table 1. Diffractogram of a bulk sample of a nickel-carbide nanostructures composite at 1100°C. Phase name Formula Figure of merit Bunsenite, syn Ni O 0.332 Nickel, syn Ni 0.247 Aluminum Nickel Ni2 Al3 1.965 Khamrabaevite, syn Ti C 0.858 Rutile, syn Ti O2 1.701

The structure of the composite material and Ni/Al-Ti reinforcing particles and elemental analysis were studied using a Zeiss Merlin scanning electron microscope with additional attachments for Oxford Instruments INCAx-act X-ray microanalysis. Elemental analysis of dispersed samples was performed for dry particles (Fig.1).

Fig. 1. Microphotography and elemental analysis of Ni/Al–TiC particles

Micrographs and elemental analysis of modified Ni particles show the presence of Ti, C, Al, and O in the surface layer. The carbon tape substrate is a cause of increased carbon content. The presence of a large amount of oxygen may indicate an oxide film on the Ni surface. However, the combined presence of Ti and C in the sample still not confirms the presence of titanium carbide. To confirm the presence of TiC in the samples, X-ray photoelectron spectra were taken (Fig. 2). To unambiguously establish the presence of the Ti-C bond, the research results were analyzed, namely, the data from the C1s and Ti2p sublevels were decrypted. The obtained spectra were recorded for a compacted composite sample without sintering. To clean the surface from the hydrocarbon film and traces of grease, the sample was etched with an ion beam. Peaks 455 eV (Ti2p) and 282 eV (C1s) confirm C-Ti bond. [NIST X-ray Photoelectron Spectroscopy Database, NIST Standard Reference Database Number 20, National Institute of Standards and Technology, Gaithersburg MD, 20899 2000]. Before ion etching, the presence of titanium oxide was also observed on the surface of the compacted sample. Based on the XPS analysis, we establish the formation of TiC on the Ni particles surface with an Al sublayer.