Zr含量对Ti-Zr-Cu-Ni钎料及钎焊接头性能的影响

采用电弧熔炼方法制备Ti-5Zr-15Cu-15Ni、Ti-10Zr-15Cu-15Ni、Ti-15Zr-15Cu-15Ni和Ti-25Zr-15Cu-15Ni 4种钛基钎料,采用4种钎料对Ti-6Al-4V板材进行搭接接头真空钎焊.对不同Zr含量的钎料的熔化特性和在Ti-6Al-4V上的润湿性进行测试,并对钎焊接头的微观组织、显微硬度和剪切强度进行测试.结果表明,Zr元素的加入对Ti-Zr-Cu-Ni钛基钎料的熔化温度有显著影响,当Zr含量为5wt%、25wt%时,钎料的固液相线温差较大,且液相线温度较高;当Zr含量为10wt%、15wt%时,钎料的固液相线温差较小,且液相线温度较低.与其他钎料成分不同,25wt%Zr含量的钎料在钎料熔化过程中存在2个明显的低熔点共晶反应,其钎料在铺展过程中出现分层现象.15wt%和25wt%Zr含量钎焊接头具有更低的显微硬度.综合钎料的熔化特性以及钎焊接头的显微硬度和剪切强度,Ti-15Zr-15Cu-15Ni是最佳的钎料成分配比,具有最好的综合性能,其钎焊接头的剪切强度为298 MPa.

Effect of Zr content on properties of Ti-Zr-Cu-Ni filler metal and its brazed joint

Four kinds of titanium-based filler metals, Ti-5Zr-15Cu-15Ni, Ti-10Zr-15Cu-15Ni, Ti-15Zr-15Cu-15Ni and Ti-25Zr-15Cu-15Ni, were fabricated by electric arc melting method, and the four kinds of filler metals were used for vacuum brazing of Ti-6Al-4V plate lap joints. The melting characteristic and wettability of the filler metals on Ti-6Al-4V were tested, and the microstructures, microhardnesses and shear strengths of the brazed joints with different filler metals were tested and analyzed. The results show that the addition of Zr has an obvious effect on the melting temperature of Ti-Zr-Cu-Ni filler metal. The gap between solidus and liquidus temperatures is wide with much higher liqiudus temperature when the content of Zr is 5wt% or 25wt%. In contrast, the gap between solidus and liquidus temperatures is narrow with lower liquidus temperature when the content of Zr is 10wt% or 15wt%. Different from other compositions of filler metals, when the content of Zr is 25wt%, there are two obvious low temperature eutectic reactions during melting process, and the filler metal appears two spreading layers phenomenon during the wetting process. And much lower microhardness was attained in the brazed joint when the content of Zr is 15wt% or 25wt%. Considering the melting characteristic of the filler metals and the microhardness and shear strength of the brazed joints, the optimized composition of the filler metal is Ti-15Zr-15Cu-15Ni, and the shear strength of the brazed joint with this filler metal is 298 MPa.