292 Prakt. Met. Sonderband 46 (2014) 
clearly distinguished, a rather homogeneous distribution of Cu and Co is visible from 20 at. % 
quantitative chemical analysis. Spatial resolution is determined by the penetration and well as 
spreading of the electron beam in the specimen (excitation volume). By the use of the very 
thin specimen (TEM lamella), the excitation volume is geometrically reduced without 
reducing the acceleration voltage and the spatial resolution of the EDX analysis can be 
clearly improved. In Fig. 2(b), the EDX line scan obtained in the SEM using the TEM 
lamella is shown. The corresponding microstructure of this specimen is shown in the TEM 
micrograph in Fig. 1. Distinct regions of high Co and high Cu concentrations, which 
indicate Co and Cu phase regions, can be resolved. From the EDX concentration plot, the 
width of the Co or Cu phase regions can be estimated to be about 0.6-1.0 um and 0.1- 
1.0 um for Co and Cu, respectively. In between the distinct phases, gradients of Cu and 
Co concentrations with a relatively large width (~0.1 um) are visible. This is not surprising, 
because the spatial resolution of the EDX analysis of the TEM lamella is given by its 
thickness (usually ~50 nm thick to be transparent for the electron beam in the SEM). 
a) TL = 
Cw! Cu 
at, „BE 
by 16%" a 
os Cu 
2 ICC 
Ha a 
0 © 3DAP a 
EE a feature 
Distance (um commor 
Fig. 2: (a) EDX line scan along the dashed line in the SEM micrograph. (b) EDX line material 
scan along a thin specimen (TEM lamella) in the SEM. enhance 
preparat 
is site-s 
3.2.3 3DAP ANALYSIS OF BULK NANOCOMPOSITES neglocte 
case 0 
To obtain information about elemental distribution on the nanometer or even atomic scale magnific 
and to determine the exact extent of alloying, 3DAP analysis can be performed. To give an Informat 
example, a 2D-composition map of the FesoCuso multiphase material after HPT with a | 
deformation is shown in Fig. 3. The distinct high concentration Fe regions indicate that spectros 
some areas are rich in Fe whereas others are rich in Cu. Some medium concentration Such in 
regions can also be detected. The level of deformation induced interfacial mixing among however 
the different phases can be determined by 1D-concentration profiles along selected demand: 
interfaces. A Cu as well as a Fe concentration profile across a smaller analysed volume 
(16x20x50nm) of the reconstruction is additionally shown in Fig.3. From this plot, grain 4. SUM 
sizes in the nanometer range can be determined. Both 1D-concentration profiles exhibits : 
distinct gradients which indicate interdiffusion. The mutual solubility of Fe and Cu is B 
normally less than 0.1 at. % at room temperature under equilibrium conditions. The Cu ulk nar 
concentration and the Fe concentration in the corresponding Fe or Cu phase is over Tultipha