Franctsevich Institute for Problems of Materials Science NAS Ukraine
Modern developments of more productive power systems are based on the principles of energy and resource saving and are associated with increasing their efficiency and increasing temperature and force loads. For such operating conditions, intermetallic matrix composites strengthened with carbides, borides or oxides are being considered, which will combine the heat- and wear-resistance of ceramics with the engineering properties of intermetallic compounds. Iron aluminides is a good matrix material in such composites due to their excellent resistance to oxidation and sulfidation at elevated temperature, as well as good fatigue and creep strength [1].
The intermetallic composites reinforced with carbide particles were produced by powder metallurgy. The mixtures obtained by planetary grinding of powders were formed into samples and heated and compacted by hot forging at 1220°C. The consolidated samples were tested for physical and mechanical properties. Compression tests were carried out at temperatures of 20 and 700°C.
The formation of the phase composition and structure of the composite occurs at each technological stage of the material production. While the carbide phase TiC (10-30 vol.%) is introduced as a whole compound and as a result of intensive milling it can be ground to a particle size of 0.7-2 µm, the oxide hardening phase FexAlyOz with a particle size of 0.08-0.2 µm is formed during the milling of powders. The formation of the matrix phase, occurs as a result of reaction synthesis during heating. A feature of the deformation structure is the formation of lamellar particles of iron aluminide 5 μm. Fine particles of the strengthening phase are located inside and mainly at the grain boundaries. With an increase in the amount of carbide phase, a decrease in the bending strength is observed from 1700/1560/1330 MPa for composition 10/20/30 vol.% TiC. Compression tests showed high yield strength — 800-1100 MPa at room temperature and 400-440 MPa at 700°C.
Keywords
Intermetallic compound, strength, hot forging, titanium carbide, powders
Acknowledgments
The work was supported by the National Research Foundation of Ukraine (project no. 2021.01/0278)
References
[1] Mitra, R. Intermetallic matrix composites: Properties and Applications. Woodhead Publishing Series in Composites Science and Engineering. 2017. 486 p.
