Development of titanium-based brazing filler metals with low-melting-point

摘要

Titanium and titanium alloy are excellent in specific intensity and corrosion resistance, and it is also good on the biocompatibility. And, the brazing is a bonding method of which productivity and reliability are high, when the complicated and precise structure is produced. Especially, the titanium base brazing filler metal is excellent in joint strength and corrosion resistance. In the other hand, when the brazing is carried out using the low-melting-point brazing filler metal, the bonding is completed without hurting characteristics of the base metal in the brazing, and the joint may become the uniform composition. In the laboratory of authors, by adding elements such as Co, Ag, Ni, Cr to the base alloy of Ti-Zr-Cu, the low-melting-point brazing filler metal has been developed. As the method, the low-melting-point brazing filler metal constituent was found by using low - melting- point eutectic search procedure in order to reduce the experiment point. As a representative brazing filler metal, in the ternary compound system, 37.5Ti-37.5Zr-25Cu alloy (melting point : 825 deg C) and in the quaternary compound system, 30Ti-43Zr-25Cu-2Cr alloy (melting point : 825 deg C) was developed. However, It was clarified that 820 deg C was limitative for the melting point, and that in present state, the melting point depression under this temperature is difficult. Conclusively, it was proven that there was the possibility as a practical brazing filler metal on author's developing brazing filler metal, as a result of considering brazing joint structure, wettability and strength characteristic after the brazing.