Kinetics of Lamellar Decomposition Reactions in U-Nb Alloys

摘要

A DC reaction has been directly observed in U-Nb for the first time. The apparent activation energies for overall transformation and DP growth are close to that for volume diffusion, contrary to expectation. Three growth models yielded the same Q values, within the bounds of error. Of the Gibbs free energy available at the start of transformation, about 75% is consumed by DP and 20% by DC. Interfacial energy plays a very minor role in retarding the DP reaction and driving the DC reaction, underscoring the significance of chemical supersaturation remaining after the DP reaction.