Experimental evaluation of particle coarsening theories

Abstract

AbstractExperiments have been carried out on coarsening of γ″ precipitates in Ni–Al and Ni–Al–Cr alloys and rate constants and particle size distributions have been determined as a function of volume fraction of γ″. These results have been compared with those predicted by the various modified Lifshitz–Slyozov–Wagner theories. An important result obtained in this investigation is that the growth rate constant increases with volume fraction of γ″ in the Ni–Al system. The Brailsford–Wynblatt encounter model has been applied to the coarsening data obtained in the Ni–Al and the Ni–Al–Cr systems and values of interfacial energies and activation energies have been determined. By applying the growth path envelope analysis to the γ′ coarsening data obtained in the Ni–Al system the ratio of the mean particle radius to the critical particle radius R/Rc and the variation of the growth rate of the particle with particle size have been determined.MST/1036