Ultrasonic soldering techniques were effectively used to pre-pare aluminum Joints with a variety of tin-base and cadmium-base low-melting solders, and the joints were evaluated by corrosion strength tests. Single-lap soldered joints indicated 20%-30% lower unit shear strengths than double-lap specimens which minimized eccentricity. Filler metal thickness showed no significant effect on strength in the thickness range of 0.003"-0.0l5". Initial double-lap specimen strengths ranged from 300 to 9000 psi, with the tin-lead series having the lowest strength and 60% cadmiura-40% tins the highest. After 8l6 hours of exposure to a corrosion environ¬ment of low-conductivity, aerated, distilled water at 95*C, the soldered joints had lost 68% to 94% of their original strengths; solders containing lead or cadmium showed poorest corrosion resis¬tance, while those composed of 97% tin-3% cerium, 97% tin-3% copper, 100% tin-trace titanium, and 96% tin-4% zinc showed relatively little strength scatter throughout the exposure period, It was recommended that ultrasonic soldering be further investigated, particularly to determine resistance of joints to other corrosive media and to investigate the effect of protective coatings on joint strength and corrosion resistance.
展开▼
