Boehm-Courjault E, Gonzales F, Jacot A, Kohler F, Mariaux A, Niederberger C, Salgado-Ordorica M A, Rappaz M
Computational Materials Laboratory, Ecole Polytechnique Fédérale de Lausanne, STI-IMX-LSMX, Station 12, CH-1015 Lausanne, Switzerland.
J Microsc. 2009 Jan;233(1):160-9. doi: 10.1111/j.1365-2818.2008.03107.x.
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.
本文介绍了一些将电子背散射衍射（EBSD）应用于凝固问题的实例。对于定向凝固的Al-Zn样品，随着锌含量从5 wt%增加到90 wt%，该技术能够揭示枝晶生长方向从<100>到<110>的变化。还研究了相应的织构演变和晶粒选择机制。在Al-X样品（X = Zn、Mg、Ni、Cu）的某些凝固条件下形成的孪晶枝晶被明确识别为<110>枝晶主干在其中心被一个（111）孪晶面分裂。在钢板上的Zn-0.2 wt% Al热镀锌涂层中，EBSD清晰地揭示了晶核的优先基面取向分布以及<1010>枝晶更快生长对这种分布的强化作用。此外，在Al-Zn-Si涂层中，在单个晶粒内测量到了高达10度mm(-1)的取向差。最后，在低生长速率下Cu-Sn包晶系统中形成的复杂带状和片状微观结构可以证明是由单个晶核引发的连续网络。EBSD还表明α相和β相具有库尔久莫夫-萨克斯晶体学关系。
