Precipitation Of Carbide Phases Research Articles

Investigation of the deformation aging of austenitic Ni36Cr11 steel

The dynamic and static deformation aging of two austenitic steels Ni36Cr11 and of commercial nickel Nil has been investigated. The activation energy of the deformation-aging process, which leads to an increase in the mechanical properties of the materials, has been determined. The value obtained for the activation energy leads to the conclusion that in the alloys investigated the movement of “divacancy-carbon atom” complexes to the dislocations takes place in the early stages of deformation aging, and as a result of this Cottrell atmospheres are formed from interstitial carbon atoms. Subsequently these atmospheres become nucleation centers for the precipitation of carbide phases. The carbides effectively pin the dislocations, and this leads to the appearance of steps on the stress-strain curves, to a rise in the hardening coefficient, and to an increase in the resistance to deformation on raising the test temperature. It is concluded that the softening which takes place at high temperatures is due to an increase in the solubility of carbon and to the agglomeration of carbides.