On the electrostatic potential assisted nucleation and growth of precipitates in Al-Cu alloy

The effect of electrostatic potential (EP), specifically without current and Joule heating effect, on the precipitation in aluminum alloy during artificial aging (180 degrees C) was investigated via microhardness testing, transmission electron microscopy (TEM), positron annihilation spectroscopy (PAS), and measurements of vacancy formation enthalpy and vacancy migration enthalpy. The results elaborated that EP promoted the nucleation of solute clusters/ GP zones in the early stage during aging. After extended aging, highly dense fine precipitates were retained in Al matrix leading to an improved strength. EP-assisted artificial aging provides a new pathway to tailor the precipitation behavior in Al alloys. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.