PSI - Issue 36

Ihor Koval et al. / Procedia Structural Integrity 36 (2022) 51–58 Ihor Koval et al. / Structural Integrity Procedia 00 (2021) 000 – 000

56 6

Fig. 4. SEM image alloy 3 (a) with spectrum points, line distribution, EDS result in binder (b).

Table 4. Chemical composition of structure elements in alloy 3.

Core

Binder

Homogeneous carbide grain

Element

wt%

at%

wt% 7.29

at%

wt%

at%

C

18.06 47.16

27.31

19.30 74.45

49.84 48.22

Ti Cr Ni

79.73 52.21 11.30 10.62

0.18 0.22 0.56 1.23

0.11 0.12 0.19 0.21

13.23 11.45 64.68 49.59

0.51 1.14 1.57 3.04

0.30 0.60 0.52 0.51

Nb

0.73 2.77

0.35 0.68

W

In the structure of alloys with 24 % (wt.) the shape of carbide grains changes to more rounded and the amount of inhomogeneous grains considerably decreases. Homogeneous carbide grains contain mainly titanium carbide and a small amount of other metals, while the binder is a solid solution of titanium and chromium based on nickel. Niobium and tungsten are distributed uniformly in both, carbide grains and binder. In alloy 3, the amount of metal carbides and binder (especially nickel) in the homogeneous carbide grains is in 2-5 times less in comparison with alloys 1 and 2. A significant amount of nano nickel causes the acceleration of titanium and carbon diffusion in the binder, the amount of which is the largest in comparison with the other alloys. Due to the small sizes of the rims, their chemical composition could not be determined. Comparison of the chemical composition of structural elements in alloys 2 and 4 with 18% (wt.) with nano and fine nickel testified, that in alloys with nano nickel in the carbide grain cores mainly tungsten diffuses, while the content of other metals of alloying carbides is not changed and the amount of nickel increases. In the rim with nano nickel, the amount of all components of the alloy is smaller in comparison with the other one, while in the binder – vice versa. EDS elemental surface distribution of the alloy 2 and 4 with 13.5% (wt.) of nano and fine nickel is presented in Fig. 6.