Transmission electron microscopy observations grain boundaries

The advent of transmission electron microscopy opened the doors to the direct observation of processes such as the pile-up of dislocations at a grain boundary and the subsequent commencement of dislocation motion in adjacent grains. The process of slip transmission described above may be seen from the perspective... 

Contemporaneously with Vohra, Michler and co-workers [32] carried out a detailed study of microwave-assisted CVD diamond film growth in methane/carbon dioxide gas mixtures on silicon wafers at different substrate temperatures (560-275°C) by XRD, transmission electron microscopy (TEM), AFM, and Raman spectroscopy. At temperatures above 430°C, the films consisted of nearly defect-free near-(112)-oriented grains with smooth (111) facets, exhibiting steps and risers at the surface. Below a transition region of 340-385°C, the film quality was much deteriorated, as evidenced by much smaller crystal size, increased twin density, and amorphous inclusions at incoherent twin boundaries. The Raman spectra (514.5-nm excitation) in the high-temperature region contained no peaks, but above the transition temperature, peaks at around 1430 and 1540 cm were evident, which the authors attributed to amorphous inclusions (Fig. 9). These observations are consistent with those of Vohra et al. [31] just mentioned. 

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... 

---