Dynamic process of nano-structured inert gas precipitates introduced with ion implantation in aluminium

Inert gas ions of Xe, Ar and Ne were implanted into Al at room temperature in a transmission electron microscope (TEM). The growth processes and the structure of inert gas precipitates were studied with conventional and high-resolution TEM (CTEM and HRTEM). Implanted Xe ions begin to segregate to atomic clusters and crystalline precipitates at a dose of ∼1.0×10¹⁸ ions m⁻² at a flux of 3.0×10¹⁶ ions m⁻² s⁻¹. The smallest size of the crystalline precipitates is ∼2.0 nm, observed with both the CTEM and HRTEM. The Xe precipitates have sizes ranging from ∼2.0 to 10 nm in specimens implanted with Xe to a dose of 5×10¹⁹ ions m⁻². The precipitates larger than ∼6 nm are usually in a non-crystalline state, but the maximum size of crystalline precipitates also depends on the surrounding environment. Analysis of the growth dynamics of Xe, Ar and Ne precipitates suggests that super-saturation, dissolving of clusters and precipitates take place during the implantation, and that these processes make the growth of the precipitates dependent on the implanted dose in a non-linear way. The smaller the size of the implanted ion, the greater this tendency.