Microstructural Evolution and Growth Behavior of In Situ TiB Whisker Array in ZrB_2-SiC/Ti6Al4V Brazing Joints

摘要

An in situ short fiber reinforced brazing technique by taking advantage of reaction between ZrB_2 and Ti has been developed for joining ZrB_2-SiC ceramic and Ti6A14V alloy. The Ag-Cu eutectic alloy was used as brazing interlayer to realize controllable growth of TiB in Ti-rich environment. The microstructural evolution of the joint was divided into four stages as experiments performed from 840℃ to 920℃. The diffusion behaviors of Ti and B may play an important role on the preferential growth of TiB whiskers during brazing. The statistics of the length of TiB showed that a rapid growth appeared at 880℃. The accommodation to the coefficients of thermal expansion by TiB whiskers was evaluated and the shear strength of the joints was tested.