Microstructural Characterization of Brazed Joints between Titanium and Stainless Steel

Optical microscopy, scanning electron microscopy, EDXA, micro-hardness and mechanical properties tests were adopted to investigate the microstructural characterization of brazed joints between tita- nium alloy, Ag95CuNiLi and stainless steel. The results showed that three layers of inter-metallic compounds had formed at the side of stainless steel/filler metal, and two zones with different microstructures had been produced at the side of titanium alloy/filler metal. At the same time, Ag diffused along the grain boundary of titanium alloy. In brazed joints, Ti and Cu enriched at the side of stainless steel, and Cu enriched near the ti- tanium alloy. The center area of the fillet is basically pure silver. Except that at the diffusion layer of the stainless steel/filler metal, the micro-hardness of other areas did not increase compared with the hardness before brazing. Joint failure analysis showed that the weakest occurred at the place near the stainless steel.