PSI - Issue 40

N.B. Pugacheva et al. / Procedia Structural Integrity 40 (2022) 372–377 N.B. Pugacheva, T.M. Bykova / Structural Integrity Procedia 00 (2022) 000 – 000

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where F - the greatest force, corresponding to the moment of destruction of the supports, N; l – distance between support axes, mm; h - height of the sample (size, corresponding to the direction of force during the trial), mm; b - width (size, corresponding to the perpendicular height), mm. The relief of the fracture surface of the samples after testing was investigated on a scanning electron microscope TESCAN VEGAII XMU. 3. Results and discussion The investigated composite had the following chemical composition, wt. %: 44.5 Fe, 25.1 Ti, 17.5 Ni, 7.0 B, 5.9 C. The matrix of the composite is a solid solution of Ni in austenite; the strengthening phases are TiC and TiB 2 , particles formed as a result of exothermic reaction: The regions of the eutectic component “γ -Fe + Fe 2 B” were found in the composite matrix (the reasons for the formation of the eutectic were considered earlier in Pugacheva et al. (2019). The inhomogeneous distribution of chemical elements and phases in the bulk of the composite (Fig. 1, Table 1) affects the distribution of micromechanical properties. The regions “ γ -Fe + Fe 2 B” indicated by ‘ 1 ’ in Fig. 2 are characterized by the highest plasticity. These areas are characterized by the maximum values of the indicators h max , φ , C IT . a b c 3Ti + B 4 C → TiC + 2TiB 2 . (5)

d

e

f

Fig. 1. Microstructure of SHS-composite with microanalysis areas (a) and distribution of elements: b - image in characteristic X-ray radiation Fe; с – Ni; d – Ti; e – C; f – B.

The plasticity of the eutectic structural component of the matrix is explained by the almost complete absence of TiC particles in it. Nevertheless, the carbon content in the austenite of the eutectic ranged from 4 to 7 at. % (spectra