Analyzing the co-sintering of Ti6Al4V/Al₂O₃ bilayer materials

Nowadays, there is a growing interest in processing of multifunctional components for several industrial applications. These components are designed as a combination of several materials with complementary properties to fulfill different functions. Powder metallurgy is able to produce components with adequate properties. Parts composed of two layers, one ceramic of Al2O3 and the other one metallic of Ti6Al4V powders, were fabricated. Powders were uniaxially pressed and then sintered by conventional and optical dilatometry to study the co-sintering. Image analysis during sintering allowed to observe the precise moment of the formation of a fissure in the Ti6Al4V layer. The cause of fissure formation was determined to be the mismatch in strain rate between layers and they appear even if the interparticle necks are already formed due to densification reached at this point. It was concluded that optimal processing conditions to fabricate defectless components can be obtained by controlling the heating rate.