Issue 68

S. Kotrechko et alii, Frattura ed Integrità Strutturale, 68 (2024) 410-421; DOI: 10.3221/IGF-ESIS.68.27

Fractographic investigations and local chemical analysis of the specimens after testing were carried out at an SEM VEGA 3 (TESCAN) equipped with EDX detector XFlash 610M (Bruker). The accelerating voltage was 20kV. High-speed video shooting took place with a GoPro-4p camera at a frequency of 240 frames per second. The resulting video in the Avidemux video editor was decomposed into separate frames. The duration of each frame was 4.2 ms.

Lattice parameters

Volume per atom, V/at, Å 3

Heat capacity, J/(g, К )

X-ray density, kg/m 3

Density, kg/m 3

a

b

c

Alloy

Phase

Å

B2

8.54 8.22 8.86 8.58 8.57 8.75 8.79 8.81

3.162 3.138 3.152 3.130 3.161 3.179 3.154 3.106

-

-

15.811 16.424 15.653 16.167 16.126 15.799 15.686 15.646

HEA12

8.44

0.253

B19`

4.1826

5.1164

B2

-

-

HEA52

8.39

0.295

B19`

4.317

4.853

B2

-

-

HEA55

8.34

0.252

B19`

4.254

4.845

B2

-

-

HEA56

8.36

0.392

B19`

4.180

4.938

Table 2: Atomic structure and physical properties.

Fracture stress

Effective value of the yield stress Yef  , М P а

Specimen diameter d 0 , mm

Specimen height h 0 , mm

Young's Modulus E, GPa

Yield stress St Y  , М P а

Plastic strain f e ,%

Alloy

f  , М P а

HEA55-1 * HEA 55-2 *

4.03 4.04 4.13 2.96 4.02

5.95 6.02 5.63 4.50 5.52

75.5 75.5 72.6 69.3 70.7

1250 1250 1269 1784 1657

2039 1881 2040 2112 1904

1645 1500 1655 1948 1781

1.57 0.96 4.20 1.80 1.13

HEA 12 HEA 52 HEA 56

* HEA55-1and HEA55-2 - specimens number 1 and 2 from the HEA55 alloy.

Table 3: Mechanical properties.

M ECHANICAL TESTING

C

ylindrical specimens were used for uniaxial compression tests (Fig. 1). These specimens were made on a lathe, followed by surface grinding. The roughness of the end surfaces did not exceed 0.63 µm. Specimen sizes are shown in Tab. 3. Tests were performed on an Instron 8802 Universal Servo-Hydraulic Machine at room temperature. The loading rate was 0.05 mm/min. Based on the test results material deformation curves were plotted in the "stress-strain" coordinates (Fig. 2).

Figure 1: Specimens for uniaxial compression.

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