Evolution of microstructural length scales during solidification of magnesium alloys
Evolution of microstructural length scales during solidification of magnesium alloys
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DOI：
10.1016/j.actamat.2012.02.055
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发表时间：
2012-05
期刊：
影响因子：
9.4
通讯作者：
S. Gurevich;Morteza Amoorezaei;D. Montiel;N. Provatas
中科院分区：
文献类型：
--
作者：
S. Gurevich;Morteza Amoorezaei;D. Montiel;N. Provatas
镁合金的微观结构通常呈现六重对称性，这不符合四重对称合金的通常特征。通过对微观结构空间分布的傅立叶分析，可以实现更系统和定量的描述。通过这种分析，从相场模拟获得的微结构揭示了具有不同尺度尺寸的自仿射区域和它们之间的交叉区域。这些空间尺度的时间演变和局部微观结构事件的分析揭示了孤立的液体池是通过遵循Aagesen等人预测的合并的普遍动力学的枝晶分支的合并而产生的，并遵循由后期冷却和反向扩散所指示的动力学而继续收缩。我们的研究结果是一致的新的实验，揭示了与主分支的间距相关的长度尺度的冷却速率的依赖性之间的相关性，和在凝固的后期阶段形成的组成相的分布和平均尺寸。
The microstructure of magnesium alloys usually presents a sixfold symmetry that is not amenable to the usual characterization of fourfold symmetric alloys. A more systematic and quantitative description can be achieved through Fourier analysis of the spatial distribution of the microstructure. Through this analysis, the microstructures obtained from phase-field simulations reveal self-affine regions with different scaling dimensions and crossover regions between them. The time evolution of these spatial scales and the analysis of local microstructural events reveal that isolated liquid pools are created through the merging of dendrite branches that follow the universal dynamics of merging predicted by Aagesen et al., and proceed to contract following the dynamics dictated by late stage cooling and back diffusion. Our results are consistent with new experiments that reveal a correlation between the dependence on cooling rate of the length scales associated with the spacing of main branches, and the distribution and average size of constituent phases that form during late stages of solidification.