基于ANSYS模拟评估Mo单晶电子束焊接焊缝中的离散晶粒

Assessment of Stray Grain Formation in Weld Joint of Single Crystal Molybdenum by ANSYS FE Simulation

摘要:

以往的研究中发现在钼单晶电子束焊接焊缝中形成了离散晶粒。本研究基于有限元模拟对杂散晶粒在钼单晶焊缝中的产生行为进行了分析。利用ANSYS软件,采用双椭球3D移动热源,对钼单晶圆管的电子束焊接接头进行有限元数值模拟。使用了用以描述晶粒离散程度的参数Φ和熔池凝固前方温度梯度G、晶体生长速度V关系的模型。通过不同焊接工艺下的模拟结果提取温度和温度梯度数据,获得G和V,计算得Φ,获得焊接功率和焊接速度对钼单晶焊缝中杂散晶粒形成的影响。

Abstract:

The stray grain was observed in electron beam welded (EBW) joint of single crystal molybdenum (Mo). Finite element (FE) method, combining the theoretical analysis, is used for evaluating the stray grain formation. Temperature-dependent thermal properties of molybdenum are incorporated in the model and a 3D volumetric moving double-ellipsoid heat source is applied. The relationship between parameter Φ, describing the degree of stray grain formation, and the thermal gradient G and the growth velocity V is used. Temperature and thermal gradient data of the model are extracted from simulation results under different operating conditions, and Φ is calculated. The effects of the welding parameters, including welding power Q and welding speed S on the formation of the weld stray grain are obtained.