Interfacial Properties of Bonded Dissimilar Materials Fabricated via Spark Plasma Sintering

This paper describes the characterization of the interfacial properties of bonded dissimilar materials for the fabrication of biocompatible composites and functionally graded materials (FGMs) with high mechanical performance. In the development of biomaterials with conflicting properties such as high strength and toughness for artificial bone, much attention has been paid to composites and FGMs consisting of biocompatible ceramics and metals. Their mechanical properties are influenced by the properties of the interfaces of dissimilar materials, and hence it is important to evaluate the interfacial properties. This study investigated the influence of combinations of materials on the interfacial strength and fracture toughness of bonded dissimilar materials consisting of four types of biocompatible materials: titanium, type 316L stainless steel, partially stabilized zirconia, and alumina. The bonded dissimilar materials were fabricated via spark plasma sintering, which is a powder metallurgy technique utilizing uniaxial load and pulsed direct current in vacuum. The interfacial strength and toughness of the materials were evaluated via compression-bend testing and indentation testing, respectively. The distributions of elements near the interfaces due to atomic diffusion during sintering were evaluated, and the influence of material combinations on the interfacial properties was considered based on the distributions. It was found that the mechanical properties of all interfaces were lower than those of monolithic materials, and the extent of the degradation in mechanical properties was dependent on the material combinations. if atomic diffusion occurred on both sides of the interface, the interfacial fracture toughness and strength tended to be relatively high.