Numerical and experimental study on the fragmentation of dendrites in the mushy zone of binary metal alloys

二元金属合金糊状区枝晶破碎的数值与实验研究

• 批准号: 62728097
• 负责人: Professorin Dr. Britta Nestler
• 金额: --
• 依托单位: Institut für Angewandte Materialien - Mikrostruktur-Modellierung und Simulation (IAM-MMS)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/62728097?language=en
• 关键词: Numerical; experimental; study; fragmentation; dendrites

Fragmentation of dendrites is a technologically important phenomenon occurring in the mushy zone of a solidifying melt, mainly during late stages of solidification. Fragmentation has a crucial impact on the grain structure of different cast parts, which in turn determines the properties of the solidified material. The goal of the proposed research project is to numerically and experimentally investigate the complex interaction of the parameters (temperature field, concentration field and interfacial energy) involved in the dendrite fragmentation, and to quantify fragmentation by detailed modelling for the first time. A fast 2-dimensional “CA stabilised diffusion model” for dendritic growth will be extended to 3 dimensions. The interaction of concentration field and capillarity will be analysed to investigate the conditions and mechanisms of fragmentation. Multiscale 2D and 3D phase-field simulations of dendritic fragmentation processes for different process conditions and under the influence of fluid flow will be performed for validation and comparison with the CA computations. In addition, experimental investigations will also be carried out for comparison and to validate the numerical model. Equiaxed microstructures with fragmented dendrites will be generated in a gradient furnace using Al-Cu alloys. A ”data base” of combinations of parameters that lead to fragmentation under diffusive conditions will be established.

枝晶破碎是一种重要的技术现象，发生在凝固熔体的糊状区域，主要发生在凝固后期。破碎对不同铸件的晶粒结构具有至关重要的影响，而晶粒结构又决定了凝固材料的性能。该研究项目的目标是通过数值和实验研究枝晶破碎中涉及的参数（温度场、浓度场和界面能）的复杂相互作用，并首次通过详细建模来量化破碎。用于树突生长的快速 2 维“CA 稳定扩散模型”将扩展到 3 维。将分析浓度场和毛细管作用的相互作用，以研究破碎的条件和机制。将在不同工艺条件和流体流动影响下对树枝状破碎过程进行多尺度 2D 和 3D 相场模拟，以进行验证并与 CA 计算进行比较。此外，还将进行实验研究以进行比较和验证数值模型。使用铝铜合金在梯度炉中生成具有碎片枝晶的等轴微结构。将建立一个在扩散条件下导致碎片化的参数组合的“数据库”。