Inconel718合金电子束焊接头组织与缺陷分析

Microstructure and Defects of Inconel718 Superalloy Joints with EB Welding Method

对Inconel718高温合金电子束焊焊缝及热影响区的气孔、微裂纹行为进行了分析。研究发现,由于焊缝金属中Ti、Al、B元素的偏析,生成γ/γ′以及Ni-B、(Ni、Cr)-Ni3B、Fe-FeB等低熔共晶,在焊接应力的作用下形成结晶裂纹。热影响区出现的液化裂纹起源于晶界处MC的不充分扩散溶解以及块状生成相的局部熔融造成溶质元素的富集。焊件焊面残留的油渍以及匙孔瞬态失衡是焊缝中形成气孔的主要因素。

The pores in weld and microfissuring behaviors in the heat-affected zone of electrom beam welded Inconel718 superalloy were studied. It is observed that the existence of γ/γ＇, Ni-B,（Ni, Cr）-Ni3B and Fe-FeB low melting eutectics in weld resulting from the segregation of Ti, A1 and B can lead to the crystallization cracks under welding stress. Liquefied cracks appearing in the heat-affect zone originating from the inadequate diffusion of MC and the enrichment of solute elements can result in partial melting of the block phase. The residual oil of welding surface and transient imbalance of keyhole are main reasons for pore formation in welded joint.