Direct TEM observation and quantification of the Gibbs-Thomson effect in a nickel superalloy

TL;DR

This study uses in situ TEM to directly observe and quantify the Gibbs-Thomson effect during precipitate dissolution in a nickel superalloy, providing insights for optimizing heat treatments.

Contribution

It presents the first direct TEM observation and quantification of the Gibbs-Thomson effect during precipitate dissolution in a nickel superalloy.

Findings

Quantified differences in precipitate dissolution related to size.

Implications for heat treatment schedule optimization.

Enhanced understanding of interface effects on phase transformations.

Abstract

Gibbs-Thompson effect is the general term referring to the influence of interfaces on the course of phase transformations such as precipitation or solidification. Whilst attention is most often focused on the Gibbs-Thomson effect on nucleation, growth and coarsening, the present study considers the reverse process of precipitate dissolution in a nickel-base superalloy during in situ TEM observation. The presence of several distinct populations of gamma-prime precipitates (primary, secondary, tertiary and grain boundary) allows the differences due to particle size to be quantified and interpreted. Important implications arise for the selection of heat treatment schedules for nickel-base superalloys and other alloy systems.