Similarities and differences in TEM and XRD characterization of several reactive milling systems

EUGENIA ZELAYA; MARCELO R. ESQUIVEL; MARIA FLORENCIA GIORDANA

San Carlos de Bariloche

Simposio; XXIII Latin American Symposium on Solid State Physics.; 2018

The main objective of reactive milling is to achieve an intermetallic as a product of two or more alleys. There are four different stages that can be clearly differentiate during reactive milling: initial, intermediate, final and completion. The initial stage is controlled by fracture process, without showing a compositional homogeneity. The intermediate one is controlled by both fracture and cold welding. At this stage, compositional changes are clearly evidenced. As milling continues, the formation of new structures is identified at the final stage. Lastly, the completion stage occurs when further milling only lead to a refinement of the sample, as in a steady state processing stage. These four stages are generally identify taking into account XRD and SEM results. The first technique gives a statistical analysis of the original alleys dissolution and the final intermetallics formation. While SEM can evaluate the morphological and size evolution of particles though the four stages. However, the combination of several TEM techniques can incorporate information about inner grain structure and partial alley segregation. Moreover, the lower detectability power of TEM techniques allows to identify the formation of intermetallics at earlier milling times than XRD. The aim of this work is to show how statistical techniques like XRD and SEM combined with TEM techniques can elucidate a complete characterization of each milling stage. To achieved this goal a summary of different systems will be presented.