PSI - Issue 6

Svetlana Atroshenko et al. / Procedia Structural Integrity 6 (2017) 259–264 Author name / Structural Integrity Procedia 00 (2017) 000 – 000

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3

the free surface velocity of the samples upon the exit of the pressure pulse to the surface were monitored by means of a differential interferometer.

3. Results and discussions

3.1. Quasi-static deformation

The results of heat release of magesium alloy during quasi-static deformation are shown in Fig. 2a, and Fig. 2b shows the calculated dependencies of deformation work -   p e d W     and of the evolving heat -    p e c Td Q     on deformation . The results of studies of energy dissipation processes in the course of quasi-static tension of metals with different rates have shown a significant dependence of the heat release intensity on the strain rate in the absence of its effect on the stress diagrams  (  ) Taylor (1934).

W,MJ/m 3

 T, 0 C

Q,MJ/m 3

 ,MPA

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4

30

250

15

5mm/min 10mm/min 20mm/min 50mm/min

200

20

5mm/min 10mm/min 20mm/min 50mm/min

10

150

100

5

10

50

0

0

0

0,00

0,05

0,10

0,15

0,00

0,05

0,10

0,15





a

b

Fig.2. Dependences  (  ) and  T(  ) - a, dependences W(  ) and Q(  ) – b

Q W

 

As a consequence of this, it turns out that the Taylor coefficient - , in contrast to the previously accepted hypotheses Rosakis et al. (2000), Zimin (2016) essentially depends on the strain rate even in the range of quasi static tests . At the same time, the magnesium alloy is characterized by a minimum Taylor coefficient among the metals studied copper M1, stainless steel 12Cr-10Ni, Steel 3, titanium alloy Ti-6Al-4V, aluminum alloy D16 (Al-Cu4Mg1), that is, most of the deformation work goes to structural transformations. Figure 3 shows the dependences of the fraction of the latent energy going to the structural transformations and characterized by the coefficient (1-  ), on deformation for different metals at the strain rate 2 1 . 10    с  . It can be seen that in a magnesium alloy a much larger part of the deformation work is spent on structural rearrangements of the material. This process, apparently, determines the high damping properties of magnesium alloys.