Scientific blog
June 2011 
Thursday, 7 July, 2011, 13:11
Posted by Piotr Bobrowski
In June I was continuing 3D-EBSD measurements on the severely deformed aluminum alloy from previous month. Additionally, an attempt to investigate a PLZT ceramic sample was made. These ceramics can be interesting because of the ferromagnetic effect occurring in them. This effect is connected with rotation of domains within grains upon magnetization of the sample. The EBSD techniques can be useful in observation of these changes of orientation within grains. Unfortunately, no indexable diffractions were observed on these ceramics. It is, probably, because of the damage of the samples surface, introduced by FIB polishing during preparations to the 3D measurements. Luckily, it turned out that, after cautious polishing, it is possible to obtain good quality diffractions and the investigations will be continued next month.
I took part in the conference entitled: “The XIVth International Conference on Electron Microscopy” which was held in Wisła in Poland. I presented a poster there. Its title was: “Three-dimensional OIM-FIB technique: selected application examples”. The abstract of the poster is givein below.

Abstract
K. Berenta, M. Bieda, A. Bigos, P. Bobrowski, M. Faryna
Three-dimensional orientation microscopy is an important tool for properties analysis of fine grain materials. The technique of 3D reconstruction of serial sections has been used to determine grain shapes, particle distributions and microstructure evolution. Fully automated 3D orientation microscopy system combines FIB and EBSD in the SEM allowing the collection of serial section of OIM data. Two examples have been selected for presentation of the 3-D FIB-OIM system capabilities: a) electrodeposited Ni coatings containing a few percent of Mo additive, b) aluminum 6013 alloy after severe plastic deformation. Nickel coatings were prepared by electrodeposition on stainless steel substrate from citrate solution. These coatings are a promising alternative to the chromium ones which, due to their toxicity, have to be eliminated from manufacturing processes. Aluminum 6013 alloy was subject to complex deformation by the KOBO method which combines extrusion with simultaneous twist of the sample. The resulting material possesses a gradient structure of the grain size distribution with fine crystallites in the outer part and elongated ones near the centre of the rod. The experimental parameters and measuring conditions were established for both materials. Along with EBSD measurements the changes of chemical composition using EDX spectrometry in 3D has been recorded. A special attention has been paid to Ga+ ion distribution as intense ion beam radiation may destroy aluminium microstructure after severe deformation. Additionally, a few attempts have been made to collect the EBSD data from serial sections of the structure of non-conductive PLZT ceramics- a piezoelectric, transparent material with wide range of potential applications.

view entry ( 622 views )   |  print article

<<First <Back | 95 | 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 | 104 | Next> Last>>