Nucleation and growth behavior of Cu–Al precipitates in He implanted and annealed aluminum

Abstract

The effects of He on the thermal evolution of Cu–Al precipitates produced after Cu + and He + implantation into pure Al foils were analyzed as a function of the implanted He fluence and post-implantation thermal annealing temperature. The profiles of Cu and He were measured via Rutherford backscattering (RBS) and elastic recoil detection analysis (ERDA) techniques. The precipitate and bubble morphology were investigated by transmission electron microscopy (TEM). In comparison to a sample implanted only with Cu +, we observe that the presence of He leads to larger Cu–Al precipitates upon low-temperature annealing. For high-temperature annealing the situation is opposite. This behavior is discussed considering precipitate nucleation and growth processes affected by the reduction in the vacancy field due to the formation of He bubbles.