High-resolution electron microscopy observations grain boundaries

Figure B.2 Symmetric large-angle (113)(TlO] tilt boundary in A1 viewed along the [110] tilt axis by high-resolution electron microscopy. The tilt angle is 50.48°. The inset shows a simulated image [4], Reprinted, by permission, from K.L. Merkle, L.J. Thompson, and F. Phillipp, Thermally activated step motion observed by high-resolution electron microscopy at a (113) symmetric tilt grain-boundary in aluminum," Philosophical Magazine Letters, vol. 82. pp. 589-597. Copyright (c) 2002 by Taylor and Francis Ltd., http //www.tandf.co.uk/journals.

K. L. Merkle, L. J. Thompson, and F. Phillipp. Thermally activated step motion observed by high-resolution electron microscopy at a (113) symmetric tilt grain-boundary in aluminium. Phil. Mag. Lett., 82 589-597, 2002. 

The overall microstructure of the bulk sample following a full creep run at 1620 K was found to have changed little from that observed following the 4-h anneal. No cavitation was observed, In order to determine the reason for the break observed in the creep curve at 1620 K, a careful TEM analysis was conducted on samples taken both before the break in cuve and after, and these were compared to a sample taken from the lower temperature creep run, 1470 K, where no break was observed. The microstructure representing the material before the break was obtained by allowing the material to deform at stresses of 50,100, and 150 MPa with a final true strain of -0.9%. The sample used to represent the microstructure after the break was deformed at stresses of 50,100,150,200,250,300 and 350 MPa with a final true strain of -1.5%. High resolution electron microscopy was used to examine the grain boundaries in each sample. 

In this chapter, the structures of grain boundaries of intermetallic compounds observed by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and field ion microscopy (FIM) were presented. Of these direct observations, the HRTEM technique espedaUy provided very significant information for example, preservation of the ordoing close to the boundary plane, preservation of the chemical ordering without rignificant local atomic... 

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