Brazing of 6061 aluminum alloy/Ti-6Al-4V using Al-Si-Cu-Ge filler metals

摘要

Al-8.4Si-20Cu-10Ge and mixed rare-earth elements (Re) containing Al-8.4Si-20Cu-10Ge-0.1Re filler metals were used for brazing of 6061 aluminum alloy/Ti-6Al-4V. The addition of 20wt.% copper and 10wt.% germanium into the Al-12Si filler metal lowered the solidus temperature from 586℃ to 489℃ and the liquidus temperature from 592℃ to 513℃. The addition of 0.1wt.% rare-earth elements into Al-8.4Si-20Cu-10Ge alloy caused remarkable Al-rich phase refinement and transformed the needle-like Al_2Cu intermetallic compounds into block-like shapes. Shear strengths of the 6061 aluminum alloy/Ti-6Al-4V joints with the two brazing filler metals, Al-8.4Si-20Cu-10Ge and Al-8.4Si-20Cu-10Ge-0.1 Re, varied insignificantly with brazing periods of 10-60 min. The average shear strength of the 6061 aluminum alloy/Ti-6Al-4V joints brazed with Al-8.4Si-20Cu-10Ge at 530℃ was about 20 MPa. Rare-earth elements appeared to improve the reaction of the Al-8.4Si-20Cu-10Ge filler metal with Ti-6Al-4V. The joint shear strength of the 6061 aluminum alloy/Ti-6Al-4V with Al-8.4Si-20Cu-10Ge-0.1 Re reached about 51 MPa.