Six decades of the Hall-Petch effect - a survey of grain-size strengthening studies on pure metals

Refining a metal's grain size can result in dramatic increases in strength, and the magnitude of this strengthening increment can be estimated using the Hall-Petch equation. Since the Hall-Petch equation was proposed, there have been many experimental studies supporting its applicability to pure metals, intermetallics and multi-phase alloys. In this article, we gather the grain-size strengthening data from the Hall-Petch studies on pure metals and use this aggregated data to calculate best estimates of these metals' Hall-Petch parameters. We also use this aggregated data to re-evaluate the various models developed to physically support the Hall-Petch scaling.