PSI - Issue 28

V.V. Balandin et al. / Procedia Structural Integrity 28 (2020) 1802–1807 V.V. Balandin et al. / Structural Integrity Procedia 00 (2020) 000–000

1804

3

Fig. 2. Deformation diagram of a titanium alloy at a deformation rate of: (a) 800 s − 1 , (b) 1500 s − 1 .

Fig. 3. (a) Dependence of the yield stress on the strain rate. (b) Dependence of ultimate strength on strain rate.

The limiting characteristics (relative contraction ψ , %) and relative elongation δ , %) ) were determined by the formulas:

L − L 0

100%

(1)

L 0 · 0 − D

δ =

D 2

2

100%

(2)

·

ψ =

D 2 0

where L and L 0 - the length of the working part of the sample after and before testing, D and D 0 are the diameter of the neck and the initial diameter of the working part of the sample, respectively. The values of the limiting characteristics of plasticity: δ and ψ of the sample after rupture, depending on the strain rate, are shown in Fig. 4. These values exceed static values ( δ = 12%, ψ = 30%), at the same time in the dynamic range of loading rates δ and ψ practically do not depend on the strain rate.