Simulation of weld solidification microstructure and its coupling to the macroscopic heat and fluid flow modelling
Simulation of weld solidification microstructure and its coupling to the macroscopic heat and fluid flow modelling
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DOI：
10.1088/0965-0393/12/1/s03
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发表时间：
2004-01-01
影响因子：
1.8
通讯作者：
Dilthey, U
中科院分区：
文献类型：
--
作者：
Pavlyk, V;Dilthey, U
显微组织对焊接接头的力学性能和完整性有很大的影响。预测焊接过程中微观结构的形成和其他凝固过程可能是技术优化的重要支持因素。如今，不断增加的计算能力允许直接模拟特定温度条件下熔融区中柱状晶粒的枝晶和细胞形态。建模进行，一方面，与有限差分细胞自动机，另一方面，与相场法。熔化焊过程中的凝固条件（温度梯度，局部凝固速率，熔池形状）的确定进行了焊接熔池流体流动和温度分布的数值宏观有限元模拟计算，如本文所述。与使用精确的物理模型一样，模拟是以微观结构的空间分辨率进行的，并且可以消除来自传统、分析或现象学模型的许多假设和限制。使用数值算法的生成和可视化的凝固过程中的微观结构形成的可能性进行了演示。应用范围从焊接和铸造到快速凝固工艺。特别是，在钨极氩弧焊定向凝固过程中的凝固条件和枝晶形态的形成的计算机模拟进行了描述。此外，模拟结果与实验结果进行了比较。
The microstructure exerts a strong influence on the mechanical properties and on the integrity of welded joints. Prediction of the formation of the microstructure during welding and of other solidification processes may be an important and supporting factor for technology optimization. Nowadays, increasing computing power allows direct simulations of the dendritic and cell morphology of columnar grains in the molten zone for specific temperature conditions. Modelling is carried out, on the one hand, with the finite difference-cellular automata and, on the other hand, with the phase field method. Determination of the solidification conditions during fusion welding (temperature gradient, local solidification rate, weld pool shape) is carried out with a numerical macroscopic finite element modelling calculation of the weld pool fluid flow and of the temperature distribution, as presented in this paper. As with the use of accurate physical models, the simulations are carried out with a spatial resolution of the microstructure, and many assumptions and restrictions from traditional, analytical or phenomenological models may be eliminated. The possibilities of using numerical algorithms for generation and visualization of microstructure formation during solidification are demonstrated. The spectrum of applications extends from welding and casting to processes with rapid solidification. In particular, computer simulations of the solidification conditions and the formation of a dendritic morphology during the directional solidification in gas-tungsten-arc welding are described. Moreover, the simulation results are compared with the experimental findings.