Effect of Diffusion Time on the Interfacial Microstructures Between the BNi5 Braze and the Nickel-Based Single Crystal DD407 Alloy [扩散时间对BNi5钎料和DD407镍基合金界面组织的影响]

作者：Xie J.; Huang Y.^*; Chen Y.; Zhang T.; Wang S.; Hao K.; Zhang C.

来源：Rare Metal Materials and Engineering, 2020, 49(12): 4348-4353.

• Brazing repair
• Diffusion time
• Interfacial microstructure
• Ni-based single crystal superalloy

The simulation defects in the nickel-based single crystal DD407 alloy were repaired by BNi5 braze. The microstructures, precipitates and element distribution of the repaired joint were observed and analyzed by optical microscope (OM), scanning electron microscopy (SEM) and micro XRD test techniques. The results show that simulation defects can be locally repaired by adopting paste BNi5 alloy. A reaction interface with elemental gradient and white Cr6Ni16Si7 particles is formed between the repaired zone and the base metal. The amount of the Cr6Ni16Si7 particles and the width of the interface increase with the increasing of the holding time. When the holding time is 120 min, the interfacial width reaches the maximum value which is approximately 224 μm. Only adopting the BNi5 alloy as the filler material is the main reason responsible for the interfacial width increasing with the holding time increasing. Further analysis of the content and the type of the filler material is needed to obtain completely repaired defects in shape and size. Moreover, further extending the diffusion time is also needed to achieve a uniform transient liquid phase welding (TLP) microstructure which is a foundation for TLP repair processing of nickel-based single crystal alloys.