Institute of Materials Science of Khabarovsk Science Center of the Far Eastern Branch of Russian Academy of Sciences, Khabarovsk, Russia:

M. A. Teslina, Researcher, e-mail: secretar@im.febras.net
N. M. Vlasova, Researcher
T. B. Ershova, Head of Laboratory of Composite Materials
I. A. Astapov, Senior Researcher

Al – C system were investigated. Relation of components in mixtures for sample production was different. The composition of initial mixture corresponded to the relation of the components 7 Ti:2 Al:3 C (Ti – 80 % (wt.), Al – 12 % (wt.), C – 8 % (wt.)). The second mixture for sample preparation consisted of the initial mixture with aluminium excess (20 % (wt.)), which corresponded to Ti – 78 % (wt.), Al – 14 % (wt.), C – 8 % (wt.). The third composition consisted of the initial mixture with titanium and carbon excess (20 % (wt.)), which corresponded to Ti – 81 % (wt.), Al – 10 % (wt.), C – 9 % (wt.). Materials with nitrogen-containing or carbon-containing MAX-phase were obtained, depending on the relation of components in mixture and sintering temperature. During the sintering of the initial mixture corresponding composition to the temperature of 1300 ^oC, the material containing MAX-phase Ti₂AlN was formed, while MAX-phase Ti₃AlС₂ was formed at the temperature of 1300 ^oC and higher. The second and third compositions, sintered at the temperature of 1300 ^oC and higher, formed a material, containing MAX-phases Ti₂AlС and Ti₃AlС₂. At the sintering temperature to 1300 ^oC, low-carbon carbonitride TiC_0.3N_0.7 was formed. Increasing the sintering temperature to 1300 ^оC and higher formed a high-carbon carbonitride TiC_0.7N_0.3. Increasing the sintering temperature from 1300 to 1400 oC changed the relation Ti₂AlC (Ti₃AlC₂) with secondary phases (TiC_0.7N_0.3 or TiC), which always are in the final product. Nature of change of microhardness of the investigated samples showed that carbonitride particles are the reinforcing phase in the material. The optimal conditions (1300 ^оC sintering temperature, 1–2 hours sintering duration), allow the obtaining of carbon-bearing MAX-phases Ti₃AlС₂ and Ti₂AlС and highcarbon carbonitride TiC0.7N0.3 in material. Relation of components in mixture plays the most important role for Ti₂AlС and Ti₃AlС₂ formation.

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