TEM Investigation on Stress Contrast and Interfaces of Contacting Particles

An investigation on nanoparticle contacting using convergent beam electron diffraction (CBED) and high-resolution electron microscopy (HREM) is reported. Cobalt particles (5–200nm) from a solution-treated Cu–2(w/o)Co alloy were extracted and allowed to contact without pressure. The contacting stress field due to adhesion was clearly observed, and the stress field had a dipole character. Free particles were observed to contact along low-index zone axes and with specific orientation relationships. Fourier transformation of the HREM micrographs revealed a highly distorted area along the contacting boundary containing dislocations. Electron-diffraction contrast from the stress fields between contacting particles was simulated, and agreed well with the experiments.