PSI - Issue 18

Vedernikova A. et al. / Procedia Structural Integrity 18 (2019) 639–644 Author name / Structural Integrity Procedia 00 (2019) 000–000

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generation in the areas in the strain localization zones. Modern infrared detectors allow us to study the evolution process of the dissipation heat and the stored energy of cold work and to proposed of methods of damage assessment (see e.g. Rosakis et al. (2000), Oliferuk et al. (2004), Chrysochoos et al. (1989), Rittel (1999)). In the present paper, we document some findings pertaining to the dissipative properties of Grade 2 and Ti-1Al 1Mn titanium alloys in deformation processes. The infrared thermography technique (IRT) used to study the evolution of heat sources and determine the critical state of materials. 2. Experimental procedure The experimental setup used for conducting the mechanical tests is shown in Fig. 1a. The quasistatic tensile experiments were undertaken with flat specimens of a titanium alloys Grade 2 and Ti-1Al-1Mn at room temperature. The chemical compositions of the materials are presented in the Table 1. Specimens with a gauge length of 120 mm and a width of 20 mm were produced from a sheet material with a thickness of 3 mm. Specimens were loaded using a 300 kN electro-mechanic testing machine Shimadzu AG-X Plus. Investigation of the heat source evolution was carried out using the temperature data generated by infrared camera FLIR SC 5000. The spectral range of the camera is 3-5 mm. The maximum frame size is 320×256 pixels, the spatial resolution is 10 -4 meters. The temperature sensitivity is from 25 mK to 300 K. The surface of the specimens intended for infrared shooting was polished in several stages and coated by a thin layer of amorphous carbon to improve the surface emissivity. Experimental setup was wrapped with protective cloth in order to avoid parasitic reflections on the surface temperature measurement (Fig. 1b). Referring to the fracture mechanics, the results for one material will be shown.

Table 1. The chemical composition of titanium alloys.

Fe

C

Si

N

Ti

O

H

Other

Grade 2

0.25

0.07

0.1

0.04

99.24 99.7

0.2

0.01

0.3

Fe

C

Si

Mn

N

Ti

Al

Zr

O

H

Other

Ti-1Al-1Mn

0.3

0.1

0.12

0.5-1.3

0.05

96.13 98.8

0.4-1.4

0.3

0.15

0.012

0.3

(a)

(b)

Fig. 1. (a) Experimental setup; (b) Protection from the effects of the parasitic reflections on the surface temperature measurement.