Joining interface and compressive strength of brazed cubic boron nitride grains with Ag-Cu-Ti/TiX composite fillers

Ag-Cu-Ti/TiX (TiX=TiB2, TiN or TiC) composite filler materials, instead of pure Ag-Cu-Ti alloy, were developed to improve the comprehensive mechanical performance of brazed joints of cubic boron nitride (CBN) grains/bonding layer/steel matrix. This article mainly concerns the effects of TiX addition on the joining interface and compressive strength of brazed CBN grains. The results demonstrate that, due to the variation of chemical activity of Ti atoms induced by TiX addition into the brazing system, the brazing reactions, especially chemical resultants produced at the joining interface between CBN grain and Ag-Cu-Ti alloy, are restrained to some extents. In general, the TiN particles show the greatest suppression effect on the brazing resultants, while the TiC particles have the weakest effect, and TiB2 particles have the medium effect. The optimum reinforcement of the composite filler is finally determined as the TiB2 particles with the content of 8 wt%, with which the average compressive strength of brazed CBN grains reaches 15 N, which is nearly the same high as that of original CBN grains.