PSI - Issue 32

M.A. Eryomina et al. / Procedia Structural Integrity 32 (2021) 284–290 Eremina/ Structural Integrity Procedia 00 (2019) 000 – 000

286

3

The technique is described in detail in previous works (see Eryomina et al. (2017) and Tarasov et al. (2010)). Corundum grit on a fabric base layer KK19XW was used as an abrasive, with a grain size of 28 –40 µm (grit M40) and 50 –63 µm (grit 5N). The second way involved wear resistance tests on a friction machine SRV III Test System, in which samples were rubbed against a steel disk (Steel 20) without lubricant. The measurements were carried out at a constant load of 10 N applied to the sample for 10 min, with a sliding speed of the sample of 2.2 m/s. The third way used a vibration module of the SRV III Test System friction machine to evaluate wear of the samples under dry friction against balls (9 mm in diameter) made of steel (ShKh15) and WC-6 wt% Co alloy. These measurement tests were performed at constant load of 10 N for 10 min, with the oscillation range of the ball being 3 mm and the frequency being 10 Hz. All the mentioned measurements were taken at room temperature. Compacts were tested in all three ways, whereas coatings being analyzed using only third way because of their low thickness of several tens of µm. 3. Results 3.1. Structural-phase state of compacts XRD analysis of the patterns shown in Fig. 1 for compacts gives the phase composition include carbides (Fe,W) 12 C and (Fe,W) 6 C, as well as some amount of tungsten and bcc Fe. The proportion of bcc Fe increases with increasing its initial fraction in the alloyed mixture of powders.

Table 1. Phase composition of samples and lattice parameters of phases.

Phasecomposition (wt %)(±3)

Lattice parameters (nm )(±0.0001)

Sample

(Fe,W) 12 C (Fe,W) 6 C

W 17

bcc Fe

(Fe,W) 12 C (Fe,W) 6 C

W

bcc Fe

1 2 3 4

35 73 50 78

47 22 44 13 38

1 4 6 9 5

1.0957 1.0946 1.0949 1.0937 1.1017

1.1115 1.1051 1.1071 1.1035 1.1114

0.3150

-

1

- - -

0.2864 0.2868 0.2874

Compacts

- -

Coating 1

4

53

0.3143

-

Table 1 shows the results of quantitative phase analysis. The lower lattice parameters observed for carbides are due to the replacement of tungsten atoms with iron.

Sample 1

Sample 2

Sample 3

Sample 4

Fig. 3. Optical images of microstructure of compacts of Samples 1- 4.