Cu-P-Sn-Ni钎料真空钎焊MGH956合金的研究

为扩展Cu-P基钎料在连接MGH956合金中的应用,采用新型Cu-P-Sn-Ni钎料对MGH956合金在800~890℃进行了真空钎焊,研究了不同钎焊温度和保温时间对焊缝组织及力学性能的影响.结果表明:在所研究的钎焊温度范围内保温5 min均可获得成形效果良好的钎焊接头,其主要由钎缝中心区和界面反应层组成,其中,钎缝中心区由α(Cu)固溶体基体和化合物Cu_3P+(Fe,Ni)_3P+FeCr组成,反应层由α(Fe)固溶体、Fe_3P和Cu_3P组成;随着钎焊温度的升高,反应层厚度逐渐增加,钎缝中心区中的化合物Cu_3P+(Fe,Ni)_3P+FeCr的形态也随之发生明显改变;各钎焊温度下获得的钎焊接头经室温拉伸,断裂均发生在钎缝中心区,断口形貌呈现韧性和脆性的混合断裂特征.830℃钎焊5 min的接头抗拉强度最大,为510.3 MPa,达到了母材抗拉强度的70.9%.

Research of brazing MGH956 alloy with Cu-Ni-Sn-Ni filler metal in vacuum

To expand the application of Cu-P based filler metal for joining MGH956 superalloy, a noval Cu-P-Sn-Ni based filler metal was developed and it was used to vacuum braze MGH956 superalloy in temperature range of 800-890℃. The effect of brazing temperature and holding time on the microstructures and mechanical properties of the joints were investigated in detail. The results show that all the brazed joints have good appearance in the brazing temperature range for 5 min. The brazed joint mainly consists of a central brazed layer and two interfacial reaction layers close to MGH956 superalloy. The central brazed layer consists of the matrix of α (Cu) solid solution and the compounds of Cu3P, (Fe,Ni)3P and FeCr. The interfacial reaction layer was composed of α (Fe) solid solution, Fe3P and Cu3P. With the increasing of brazing temperature, the thickness of reaction layer increases, and the shape of the compounds in the central brazed layer also changes markedly. The room temperature tensile fracture of all the joints occur in the central brazed layers, and the fracture is characterized as ductile and brittle mode. The maximum tensile strength of the joint brazed at 830℃for 5 min can be obtained at 510.3 MPa, which is 70.9% of the MGH956 parent alloy.