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镍基高温合金电子束钎焊接头界面组织及力学性能

Interfacial reaction product and mechanical properties of the electron beam brazed Ni-based superalloy joints

  • 摘要: 采用Bпp27钎料实现了K465镍基高温合金的真空电子束钎焊。分析了不同工艺参数对接头抗剪强度的影响,借助扫描电镜(SEM)、能谱分析(EDS)和相图分析等方法研究了界面结构,确定了界面反应产物及其形态分布。结果表明,在界面反应层中生成五种产物:大量的镍基γ固溶体和(γ'+γ)共晶相,大量的富含钨的Ni3B和CrB相,以及少量的NbC相;化合物相以细小的块状弥散分布在镍基固溶体中。随着束流和加热时间的增加,接头抗剪强度呈现先升高再降低的趋势。当束流为2.6 mA,加热时间为560 s,聚焦电流为1 800 mA时,获得最大抗剪强度为436 MPa的钎焊接头。

     

    Abstract: Ni-based superalloy K465 was brazed with Bпp27 filler metal by vacuum electron beam brazing, and the effects of primary processing parameters on shear strength of joints were investigated.Microstructure of the brazed joints with Bпp27 filler metal is studied by scanning electron microscopy (SEM), energy disperse spectrum (EDS) and X-ray diffraction (XRD).The results show that the structure of brazing seam consists of a large amount of γ solid solution, (γ'+γ), richW in Ni3B and CrB, and a small quantity of NbC.With the beam current and heating time increasing, the tendency of shear strength of the joints firstly increased, and then decreased.The excellent shear strength of the joints is 436 MPa when the beam current of welding is 2.6 mA, heating time is 560s and focused current is 1 800 mA.

     

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