PSI - Issue 41

S.V. Uvarov et al. / Procedia Structural Integrity 41 (2022) 610–617 Author name / Structural Integrity Procedia 00 (2019) 000–000

612

3

of the IR radiation in the water. We have tested disk-shaped specimens of two different materials: titanium alloy VT6 (further in the text is designated as «VT6») and vanadium alloy VnP-1 (further in the text is designated as «VnP-1»). Tables 1 and 2 are show the composition of metals and sample parameters.

Table 1. Chemical composition of metals. Sample

The norm of the content of controlled impurities, %, no more Fe Al Si N H O C

VnP-1

0.15

0.2 Al

0.2 Fe

0.01

0.001

0.03 0.03

Ti

Zr

V

VT6

base

5.3-6.8

≤0.6 ≤0.3

3.5-5.3

Table 2. Sample parameters.

c 0 , m/s

ρ 0, kg/m

σ*, GPa

# Sample

W, J

D, mm h, mm

Al foil (0.07 mm)

ε˙*, 10 6 1/s

3

#1 (VT6_3) #2 (VT6_5) #3 (VT6_6) #4 (VT6_8) #5 (VT6_4) #1 (VnP-1_3) #2 (VnP-1_4) #3 (VnP-1_5) #4 (VnP-1_6)

9.20 9.20 9.20 9.20 9.15 9.20 9.15 8.76 8.92

13 13 13 13 13 9.9 9.9 9.9 9.9

0.89 + 0.94 +

5290 4450

0.1 2.0 4.1 6.5 3.3 3.8 -

0.4 1.5 2.4 3.3 0.6 3.4 -

0.91 without 0.91 without

0.81 + 0.84 + 0.81 +

4950 6110

0.86 without 0.86 without

-

-

5.0 4.8 Velocity profiles of free surface of the sample were recorded at the rear side of the specimen using FDVI Mark IV 3000 VISAR systemMartin Froeschner & Associates Optoelectronics, the Tektronix DPO 7254 Oscilloscope. Before the experiment, the beams of VISAR and loading lasers were aligned. To study the effect of laser loading on the material, metallographic sections were made in the cross-section of the sample passing through the impact zone as shown in Fig. 1. Samples were pressed into transparent acrylic to improve the quality of grinding and hold the edge of the sample. Preparation of the metallographic section included mechanical grinding using P120 to P2500 grit, polishing on felt with 1 µm diamond paste, and finishing polishing using 0.04 µm oxide suspension. During analyzing the internal structure of the sample, the metallographic sections were sequentially reground to move the plane of the metallographic section through the entire impact zone (from 0 to 100%, see Fig. 1). It should be specially noted that vanadium is extremely difficult to polish and to etch, and information on vanadium metallography in the literature is extremely scarce and not numerous. The samples were studied both in the unetched state (including for measuring microhardness) and after chemical etching. Vanadium thin sections were etched using: Murakami's reagent (10 g K4[Fe(CN)6] + 10 g KOH + 100 ml H2O), Oberhofer’s reagent reagent (100 cm3 H 2 O + 100 cm 3 C2H5OH + 0.1 g SnCl + 0.2 g СuСl + 6 g FeCl + 10 cm 3 HCl), aqueous solutions of HF + HNO 3 in various concentrations. To reveal the microstructure of the titanium alloy, an aqueous solution of 5 % HF + 5 % HNO 3 was used. As Fig. 1 shows the microhardness was measured on a metallographic section passing through the middle of the impact zone. On each sample, a series of measurements were made in the following areas:  Parallel to the front surface at a distance of 0.15 mm from it (“Front”)  Parallel to the rear surface at a distance of 0.20 mm from it (“Rear”)  In the impact zone in the direction of shock wave propagation: in the center (“Line 2”), as well as 0.25 mm above (“Line 1”) and 0.25 mm below (“Line 3”)  Outside the impact zone to assess the distribution of microhardness over the thickness of the sample (Base)