Effect of Nb solutes on the Kolbe mechanism for microtwinning in Ni- based superalloys

VV Borovikov and MI Mendelev and NA Zarkevich and TM Smith and JW Lawson, INTERNATIONAL JOURNAL OF PLASTICITY, 178, 104004 (2024).

DOI: 10.1016/j.ijplas.2024.104004

As the operating temperature of jet turbine engines increase, creep becomes the life-limiting property for turbine disks and blades. At intermediate temperatures, around 600-800 degrees C, microtwinning contributes significantly to creep strain in these alloys. Therefore, understanding how microtwins form and grow is critical to improving the creep life of future Ni-base superalloy components. In addition, exploring the effect of different alloying elements, such as Nb and Ta, on the formation of microtwins is critical for future alloy development. Several mechanisms of microtwinning have been proposed among which the Kolbe mechanism, based on thermally activated reordering, is believed to be dominant. In this work we employ atomistic simulation to investigate the effects of Nb solutes on the Kolbe mechanism. The simulation demonstrates that Nb atoms significantly slow down the reordering processes, explaining the experimentally observed improvement in the creep resistance.

Return to Publications page