镍基单晶高温合金凝固缺陷研究进展

Advance in Research of Casting Defects of Directionally Solidified Nickel-based Single Superalloys

镍基单晶高温合金的凝固缺陷对其力学性能有很大的影响,减少和控制凝固缺陷对提高合金性能和降低成本具有重要意义。综述了镍基单晶高温合金定向凝固过程中可能出现的几个重要缺陷,包括缩松、雀斑、晶体取向的偏离和杂晶,重点讨论了这些缺陷的特点和产生的机理,并从合金成分、工艺参数、铸件结构等方面分析了凝固缺陷的影响因素,指出了减少单晶高温合金凝固缺陷的措施。

Casting defects are deleterious to the mechanical properties of nickel-based single superalloys,the decrease of casting defects is benefit for improving mechanical properties and reducing the cost.Some important casting defects formed in the directional solidification process are discussed,including porosity,freckles,misorientation and stray grains.Based on the features and formation mechanisms for the defects,the influence of alloy composition,processing parameters and casting structure on the casting defects is analyzed.Meanwhile,the suggestions for reducing casting defects are pointed out.