Prediction of solidification behaviour via microstructure models based on granular structures
Prediction of solidification behaviour via microstructure models based on granular structures
复制标题
通过基于颗粒结构的微观结构模型预测凝固行为
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
Peter D. Lee
中科院分区：
文献类型：
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作者：
A. Phillion;S. Vernede;Michel Rappaz;Steve Cockcroft;Peter D. Lee
摘要利用基于颗粒结构的微观组织模型，对影响热裂的两个重要因素-半固态本构行为和晶粒渗流进行了模拟。半固体模型几何形状基于修改的Voronoi镶嵌，并且包括圆角以近似等轴球状晶粒结构，其中液体围绕晶粒。逾渗模型结合了凝固和热力学方面来预测糊状区域内从连续液体到连贯固体网络的逐渐过渡，而本构行为模型使用实验得出的数据来描述固体颗粒的行为。通过在晶粒尺寸和固体分数的范围内进行一系列模型运行，模拟揭示了晶粒尺寸，半固态屈服应力，应变局部化和晶粒聚结之间的重要联系。此外，模型提供了洞察力的相对重要性，热裂形成的每种机制，并显示改善定量热裂预测的承诺。
Abstract Two important factors affecting hot tearing – semi-solid constitutive behaviour and grain percolation – have been simulated through the use of microstructure models based on granular structures. The semi-solid model geometry is based on a modified Voronoi tessellation, and includes rounded corners to approximate an equiaxed-globular grain structure with liquid surrounding the grains. The percolation model combines solidification and thermodynamic aspects to predict the gradual transition within the mushy zone from a continuous liquid to a coherent solid network, while the constitutive behaviour model uses experimentally-derived data to describe the behaviour of the solid grains. By performing a series of model runs over ranges of grain size and fraction solid, the simulations have revealed an important link between grain size, semi-solid yield stress, strain localisation, and grain coalescence. Furthermore, the models provide insight on the relative importance of each mechanism on hot tear formation, and show promise for improving quantitative hot tearing predictions.