Plastic flow properties and fracture toughness characterization of unirradiated and irradiated tempered martensitic steels

Influence of the temperature on the tension behaviour of EUROFER97 alloy at high strain rate

“…11. Indeed, adding the results obtained at high strain rate to those obtained in quasi-static regime [2] at 9·10 −5 s −1 can be highlighted how the strain rate vertically moves the curve. The behaviour is well described by an exponential function.…”

“…The final thermal treatment applied consisted of austenitization during 0.5h @ 980 • C + air cooling followed by tempering 1.5 h @ 760 • C + air cooling. A detailed description of the microstructure of the Eurofer97 can be found in [2] and [3]. Here, it suffices to say that the material features small prior austenitic grains, characterized by a mean intercept length of about 10 µm.…”

“…On the other hand, there are other models based upon physical concept such as Zerilli-Armstrong material constitutive model [11], based upon dislocation mechanics. Others authors based their constitutive model upon dislocation density [2,3,6]. To describe the influence of temperature effect on the dynamic behaviour of Eurofer97, that is a body centered metal [1], the Zerilli-Armstrong was used.…”

“…where, c 1 , c 3 , c 4 , c 5 and n are the five material constants for the bcc model, while c 0 take into account the influence of the dislocation density on the yield stress [2], evaluable as follow:…”

“…This last parameter was chosen equal to 55 MPa thanks to a previous investigation of the plastic flow properties in tension of the Eurofer97 steel [2]. As a first approximation, the obtained five material constants are collected in the following Table 1.…”