Large tensile strains acting on the solidifying weld metal can cause the formation of eutectic bands along grain boundaries. These eutectic bands can lead to severe liquation in the partially melted zone of a subsequent overlapping weld. This can increase the risk of heat-affected zone liquation cracking. In this paper, we present a solidification model for modeling eutectic bands. The model is based on solute convection in grain boundary liquid films induced by tensile strains. The proposed model was used to study the influence of strain rate on the thickness of eutectic bands in Alloy 718. It was found that when the magnitude of the strain rate is 10 times larger than that of the solidification rate, the calculated eutectic band thickness is about 200 to 500% larger (depending on the solidification rate) as compared to when the strain rate is zero. In the paper, we also discuss how eutectic bands may form from hot cracks.

中文翻译：

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模拟应变率对共晶带厚度影响的数值模型

作用在凝固的焊接金属上的大拉伸应变会导致沿晶界形成共晶带。这些共晶带会导致随后重叠焊缝的部分熔化区域中严重的液化。这会增加热影响区液化开裂的风险。在本文中，我们提出了一种用于建模共晶带的凝固模型。该模型基于拉伸应变在晶界液膜中的溶质对流。该模型用于研究应变速率对718合金中共晶带厚度的影响。发现，当应变速率的大小是凝固速率的10倍时，与应变速率为零时相比，计算出的共晶带厚度要大200到500％（取决于凝固速率）。在本文中，我们还讨论了热裂纹如何形成共晶带。