Determination of the Fe content of embedded Cu-rich particles in ferritic alloys using energy-filtered TEM.

A novel technique for the quantification of the iron content of copper precipitates in ferritic steels is presented. Energy-filtered (EF) imaging has been used to extract elemental maps with high spatial resolution. These maps contain enough information to attempt the quantification of the signal produced by the precipitates when either a line profile is measured across them or the whole image signal is integrated. Assumptions such as sphericity of the precipitates and composition variations are discussed. Special attention to the assessment of drift on the information extracted from EF images has been taken. Minimum detectability and optimum acquisition conditions are discussed.

A versatile double aberration-corrected, energy filtered HREM/STEM for materials science.

A HREM/STEM incorporating aberration correctors in both the probe-forming and imaging lenses has been installed at Oxford University. This unique instrument is also equipped with an in-column energy-loss (Omega-type) filter, HAADF detectors above and beneath the filter, and an EDX system. Initial tests have shown it to be capable of approximately 0.1 nm resolution in both TEM and HAADF STEM imaging modes. Some examples of applications are finally presented.