The Precession Technique in Electron Diffraction and Its Application to Structure Determination of Nano-Size Precipitates in Alloys

Abstract

Crystal structure of nano-scale precipitates in age-hardening aluminum alloys is a challenge to crystallography. The utility of selected area electron diffraction intensities from embedded precipitates is limited by double scattering via matrix reflections. This effect can be signally reduced by the precession technique, which we have used to collect extensive intensity data from the semicoherent, metastable η′-precipitate in the Al-Zn-Mg alloy system. A structure model in the space group P-62c is proposed from high-resolution microscopy and electron diffraction intensities. The advantages of using the precession technique for quantitative electron diffraction is discussed.

Automated nanocrystal orientation and phase mapping in the transmission electron microscope on the basis of precession electron diffraction

“…Ref. [14][15][16][32][33][34][35][36][37], and also suppresses Kikuchi lines and other crystal thickness related effects. Precession ED spot patterns possess an increased number of observable ED spots with respect to standard (stationary or zero-precession-angle) primary electron beam ED spot patterns.…”

SBA-15 as Support for Ni–MoS2 HDS Catalysts Derived from Sulfur-containing Molybdenum and Nickel Complexes in the Reaction of HDS of DBT: An All Sulfide Route

“…5c. For the identification of the crystalline Ni-S phase, the quasi kinematical intensity inside precession electron diffraction patterns [22][23][24][25][26] was analyzed. The experimental pattern of Fig.…”

Precession Electron Diffraction – a versatile tool for the characterization of Phase Change Materials

“…Space group determination is complicated using selected area electron diffraction (SAED) since the zonal and serial reflection conditions can be violated by multiple scattering. In many cases the less dynamic intensity in PED patterns enables the ab-initio structure determination of unknown and nanoscale crystals [3,4] with the aid of direct methods [5].…”