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

375

4

4, 5, and 6 in Table 1 and in Fig. 1). Probably, during the synthesis, along with the exothermic reaction (5), the diffusion saturation of austenite with carbon occurred throughout the entire volume of the composite.

Table 1. The chemical composition of the areas marked in Fig. 1, а , а t. %. Spectra B C Si Ti Cr Fe

Ni

Phases

1 2 3 4 5 6 7 8 9

32.84 29.78 26.76

4.18 5.06 6.25 5.74 6.67 7.10

0 0 0

0.38 0.38 0.80 0.78 0.81 1.34 5.34

0.74 0.72 0.43 0.25 0.41 0.42 0.21 0.30 0.21 0.25 0.10 0.27 0.38 0.15 0.18 0

54.64 55.05 53.10 60.00 61.44 64.95 53.43 17.37 36.90 32.51 27.23 12.15 26.42 44.93 34.87 26.49

7.21 9.00

Fe 2 B Fe 2 B Fe 2 B

12.67 32.69 29.22 25.78 25.14

0 0 0 0 0 0 0

0.55 0.47 0.42 0.46

γ -Fe + TiC γ -Fe + TiC γ -Fe + TiC γ -Fe + TiC γ -Fe + TiC γ -Fe + TiC γ -Fe + TiC γ -Fe + TiB 2 γ -Fe + TiB 2 γ -Fe + TiB 2 γ -Fe + TiC γ -Fe + TiC

15.41 28.26 25.19 29.29 18.93 24.93 11.84 21.39 27.24 16.41

0 0

47.76 24.47 23.04 25.14 39.76 16.50 20.60 21.43 20.77

6.62

13.15 14.62

10 11 12 13 14 15 16

0.33 0.19 0.16 0.15 0.21 0.30 0.23

18.48 18.02 35.92

9.78 4.88 8.90

0 0

12.49 16.01 10.08

25.85

γ -Fe + TiB 2 + TiC

Upon cooling in the austenite of the eutectic, TiC nanoparticles were homogeneously precipitated, similar to the previously considered process of homogeneous precipitation of nanosized strengthening particles upon cooling a supersaturated solid solution. It was shown earlier by Pugacheva et al. (2014), that Fe 2 B particles have properties similar to austenite and are plastic. Therefore, the plasticity characteristics of the “ γ -Fe + Fe 2 B ” eutectic are higher in comparison with other structural components of the composite (Table 2). The maximum strength corresponds to areas with strengthening particles TiC and TiB 2 (Fig. 2, Table 3). The micromechanical properties of the regions “γ Fe + TiC” (denoted by ‘ 3 ’ in Fig. 2) and “γ -Fe + TiB 2 + TiC” (denoted by ‘ 4 ’ in Fig. 2) are approximately the same (Tables 2 and 3). Since TiB 2 particles are characterized by higher hardness compared to TiC), the loading diagram for regions ‘ 4 ’ is slightly shifted to the left relative to regions ‘ 3 ’ . Areas designated ‘ 2 ’ in Figure 2 differ from areas ‘ 3 ’ by a lower carbon content, and hence by a lower amount of TiC particles. Loading diagram for regions ‘ 2 ’ in Fig. 2 is slightly shifted to the right.

Fig. 2. Loading diagrams of structural components of the composite: 1 - eutectic “ γ -Fe + Fe 2 B ” , 2 – austenite; 3 – “ γ -Fe+ TiC” ; 4 – “ γ -Fe+TiB 2 ” .