Understanding the residual stress distribution in brazed polycrystalline CBN abrasive grains

Abstract

This article investigates the brazing-induced residual stresses in the polycrystalline cubic boron nitride (PCBN) abrasive grains based on finite element simulation. The effects of embedding depth and gap thickness on the residual stress distribution in brazed PCBN grains are discussed. Results obtained show that, compared with the Ag-Cu-Ti alloy joining CBN grains and AISI 1045 steel substrate, the AlN binder materials in the polycrystalline CBN grains always have a greater effect on the brazing-induced residual stresses; meanwhile, large residual tensile stresses usually exist at the interface between the microcrystalline CBN particles and AlN binders. In comparison to the embedding depth, the gap thickness has little influence on the brazing-induced residual stresses. Furthermore, compared with the other embedding depth, in the case of the embedding depth of 40 %, the residual stresses in the brazed PCBN grain are generally the lowest in the grain bottom and the largest in the grain top surface. Finally, the finite element model applied in the current simulation work is validated through measurement experiments of the brazing-induced residual stresses in the monocrystalline CBN grain.