纵向静磁场对单晶高温合金DD483组织及蠕变性能的影响

摘要

The influence of various longitudinal magnetic fields on the microstructures,micro segregation,precipitation and the creep properties of single-crystal super alloy was studied by directionally solidifying super alloy DD483 under various longitudinal magnetic fields.The results showed that the characteristic growth of the single-crystal alloy was destroyed by the magnetic field.The dendrite morphology was destroyed to form freckle when the magnetic field was strong enough.The magnetic field had little effect on the primary dendrite arm spacing.But it relieved the micro segregation,obviously refined the γ'-phase size on the primary dendrite arm and lowered the content and size of carbides and eutectic structure.The rupture life and creep strain were decreased due to the single crystal was destroyed by the magnetic field.%在静磁场下进行高温合金DD483的定向凝固实验,研究了不同磁场强度对单晶镍基高温合金DD483凝固组织枝晶形貌、合金元素偏析系数、析出相和蠕变性能的影响.结果表明:纵向静磁场的施加使高温合金DD483单晶生长性受到破坏,强的磁场使得枝晶定向生长形态受到破坏,形成“雀斑组织”,对一次枝晶间距影响不大.施加磁场使得该单晶合金中合金元素的偏析降低；也使单晶高温合金DD483凝固态组织中γ’析出尺寸降低、碳化物和共晶组织尺寸和含量显著减小.同时磁场对该合金的单晶性和枝晶的定向生长行为的破坏使得合金的蠕变性能降低.