Quantification of Precipitation Hardening and Evolution of Precipitates

Quantification of precipitation hardening is a challenging subject as it demands combined knowledge of precipitation strengthening mechanism and precipitate growth/coarsening kinetics. Having not seen many attempts on developing new theories in recent years, the authors are aware of the fact that many existing concepts and developed theories are sometimes even neglected or misused. This article therefore aims to describe overview on some aspects which have not been fully addressed and/or misused. Recent developments in this subject include an accurate determination of the equilibrium precipitate fraction and interparticle spacing. The influence from precipitation fraction on precipitate coarsening and hardening kinetics was accounted for quantitatively, which allows the hardening quantification to be carried out in a more accurate manner. In addition, difficulties in quantification of precipitation strengthening effects in commercial systems are discussed. Advanced theories on dislocation precipitate interaction mechanisms are required to improve the accuracy in quantification of precipitation hardening to a high level.