EBSD: a powerful microstructure analysis technique in the field of solidification
This paper presents a few examples of the application of electron back-scatter diffraction (EBSD) to solidification problems. For directionally solidified Al-Zn samples, this technique could reveal the change in dendrite growth directions from < 100 > to < 110 > as the composition of zinc increases from 5 to 90 wt%. The corresponding texture evolution and grain selection mechanisms were also examined. Twinned dendrites that form under certain solidification conditions in Al-X specimens (with X = Zn, Mg, Ni, Cu) were clearly identified as < 110 > dendrite trunks split in their centre by a (111) twin plane. In Zn-0.2 wt% Al hot-dip galvanized coatings on steel sheets, EBSD clearly revealed the preferential basal orientation distribution of the nuclei as well as the reinforcement of this distribution by the faster growth of < 1010 > dendrites. Moreover, in Al-Zn-Si coatings, misorientations as large as 10 degrees mm(-1) have been measured within individual grains. Finally, the complex band and lamellae microstructures that form in the Cu-Sn peritectic system at low growth rate could be shown to constitute a continuous network initiated from a single nucleus. EBSD also showed that the alpha and beta phases had a Kurdjumov-Sachs crystallographic relationship.
Keywords: Aluminium alloys ; Ebsd ; Oim ; peritectic copper alloys ; solidification ; Dendrite Growth Directions ; Peritectic Alloys ; Aluminum-Alloys ; Texture Evolution ; Cu-Sn ; Diffraction ; Crystal ; Systems ; Phase ; Selection
Record created on 2010-11-30, modified on 2016-08-09