Sn改性Ti-Zr-Cu-Ni钎料的微观组织和力学性能

采用自制Ti-Zr-Cu-Ni-Sn钎料钎焊TA2钛合金，研究了不同Sn元素含量改性Ti-Zr-Cu-Ni钎料的熔化特性、微观组织及物相、润湿及熔蚀性、接头拉伸强度。研究表明，Sn含量增加，Ti-Zr-Cu-Ni-Sn钎料固、液相线温度基本升高，但温度差值基本变窄，可更好地抑制钎焊界面脆性化合物形成。Ti-Zr-Cu-Ni-5Sn钎料组织由Ti、Zr基体和晶体相构成，Sn倾向与Ti、Zr结合形成Ti₂Sn₃、Ti₆Sn₅、Zr₅Sn₃等低熔点共晶相。Sn≤1.5%时，随Sn含量增加，钎料对TA2钛合金的润湿性逐渐变差；继续增加Sn,钎料润湿性改善，添加5%Sn的钎料对基体润湿最佳。添加5%Sn并降低Cu、Ni总量的改性钎料对TA2钛合金熔蚀减弱。相同钎焊工艺下，添加5%Sn接头的强度和塑性均有提升。钎焊温度升高，Ti-Zr-Cu-Ni钎料产生更多强化物相，致接头强度大幅提升，而Ti-Zr-Cu-Ni-5Sn钎料产生的含Sn物相强化作用对接头强度提升有限；相...

Microstructure and mechanical properties of Sn-modified Ti-Zr-Cu-Ni filler metals

Using self-made Ti-Zr-Cu-Ni-Sn filler metal to braze TA2 titanium alloy, the melting characteristics, microstructure and phase, wetting and corrosion resistance, and tensile strength of joints of modified Ti-Zr-Cu-Ni filler metals with different contents of Sn were studied. The results show that with the increase of Sn content, the solid and liquidus temperature of Ti-Zr-Cu-Ni-Sn filler metals basically increase, but the temperature difference is basically narrowed, which better inhibits the formation of brittle compounds at the brazing interface. The microstructure of the Ti-Zr-Cu-Ni-5Sn filler metals is composed of Ti, Zr matrix and crystal phase. Sn is more inclined to combine with Ti and Zr to form low melting point eutectic phases such as Ti₂Sn₃, Ti₆Sn₅, Zr₅Sn₃, et al. When Sn≤1.5%, the wettability of this filler metal to the TA2 titanium alloy is gradually deteriorated. Continuing to increase the Sn, the wettability of the filler metal is improved, and the filler metal containing 5%Sn has the best wetting to the matrix. The erosion of TA2 titanium alloy is weakened by adding 5%Sn and reducing the total amount of Cu and Ni. Under the same brazing process, the strength and plasticity of the brazed joint with 5% Sn are improved. With the increase of the brazing temperature, the Ti-Zr-Cu-Ni filler metals produces more strengthening phases, which leads to a significant increase in the strength of brazed joint, however, the strengthening effect of Sn-containing phase produced by Ti-Zr-Cu-Ni-5Sn filler metal on strength of brazed joint is limited. In contrast, the brazing temperature has a greater impact on the strength of brazed joints.