Effect of Dynamic Strain Aging on Tensile Deformation of 20MnMoNi55 Alloy

Material modelling for dynamic strain ageing phenomenon of alloy 20MnMoNi55

“…The material investigated in this work is 20MnMoNi55 low alloy steel used in the reactor pressure vessel of Indian PHWR, which operates at 300°C at 90 bar pressure. Detailed investigations of tensile deformation with DSA effect have been reported by the same author [9]. The chemical composition and mechanical properties are given in Tables 1 and 2.…”

“…The major constituents are ferrite and bainite phases with traces of retained austenite.

Figure 1 Optical Microstructure of alloy 20MnMoNi55 [9].

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“…A large number of tensile tests have been conducted by the same author for temperature range varying from room temperature (RT) to 450°C with varying strain-rate of 10 −5 –10 −2 s −1 which have been reported in the work of [9]. For the sake of completeness, a few results have been reproduced here.…”

“…Serrated/Jerky stress–strain curve shows PLC effects, which indicate DSA and negative strain-rate sensitivity.

Figure 2 Stress–strain responses at different strain-rates.

Figure 3 Typical types of Serrations of alloy 20MnMoNi55 [9].

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“…The presence of Manganese ( Mn ) alloy in the material results in an increase in the activation energy for DSA [8] because of the formation of Mn-C , Mn-N pairs. This, in turn, reduces the mobility of C and N atoms and hence a higher activation is required [9].…”