STUDY OF M23C6 PRECIPITATION IN A 45Ni-35Cr-Nb ALLOY

Matías Sosa, Alejandro Sepulveda Buitrago, Alberto Carlos Picasso
2019 Acta Metallurgica Slovaca  
<p class="AMSmaintext">The 45Ni-35Cr-Nb alloy, commonly known as ET45 micro, produced in the form of centrifugally cast tubes, was studied by means of optical microscopy after aging treatments at 1073 and 1173 K for different times. A description of M<sub>23</sub>C<sub>6</sub> secondary carbides precipitation phenomenon was made as a function of time. The purpose of carrying out a kinetic study of the precipitation of this phase is to be able to calculate the activation energy required for
more » ... dary precipitation. This allows to infer what is the mechanism associated with it. Analysis after using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model showed that secondary carbide precipitation occurs in a single stage. It was found that this phenomenon, which is assisted by diffusion, has an activation energy of 196 kJ/mol. This value would indicate that the diffusion of Cr atoms in the austenitic matrix is the phenomenon that dominates the precipitation of the M<sub>23</sub>C<sub>6</sub> secondary carbide.</p>
doi:10.12776/ams.v25i3.1312 fatcat:nrha7x2rkveqfcfsdkerxggzcu