Study of deformation mechanisms to creep in austenitic steel

Abstract

The objective of this work is to study the deformation mechanism’s in three Cr – Ni – Fe alloyed austenitic steels, when they operate for long periods of time at high temperatures and high stress states, in these conditions the material is subject to creep deformation, which is the responsible for the loss of mechanical properties.

Tensile creep tests are performed at a temperature range between 978 and 1173 K, and applied stresses between 70 and 110 MPa in the material reception. From experimental data the characteristic parameters are calculated such as the creep coefficient of tension and activation energy.

The microstructural variation of the material is also analyzed with optical microscopy and scanning electron microscopy (SEM) and analysis by dispersive X- ray spectroscopy (EDX), to evaluate the effects of kinetics changes occurred in the precipitated phases and the presence of microstructural damage.