Abstract
We have investigated an effect of vanadium or aluminum into titanium alloys on the formation of Kirkendall voids in titanium region in diffusion bonds between titanium and molybdenum. The influence of bonding conditions on the joint stregnth has been also investigated. The bondings were performed under bonding temperature range from 1023 to 1473 K and bonding time range from 0 to 250 ks in a vacuum of 8 mPa. Main results obtained are as follows. The Kirkendall voids were observed in the bonded zone of the Ti-4.04at%Al/Mo joint. On the other hand, when Ti alloys had more than 1.89 at%V, the void were not observed at the bonded zone of the Ti-V alloys/Mo joint. The void fraction on the bonded zone of the Ti-V alloys having the vanadium content less than 0.95 at% were decreased with increasing the vanadium content. The concentration of vanadium in the vicinity of the voids was higher than the average concentration of the Ti-V alloy containing less than 0.95 at%V. When the bonding time was 1.8 ks, the joint strength of the joint of TB340B/Mo was maximum value of 200 MPa. The tensile strength of joints of the Ti-4.04 at%Al/Mo and Ti-1.89 at%V/Mo reached about 340 MPa. On the other hand, the joint strength was increased with increasing the vanadium content of the Ti-V alloys having vanadium content range from 0.11 to 3.64 at%.
