Development and analysis of functionally-graded SiAlON composites with computationally designed properties for cutting inserts

There is an increasing demand for developing new cutting tools with exceptional thermomechanical and tribological properties to meet the growing demands of the machining industry. By introducing a novel concept of functionally graded (FG) materials, the work aims to develop a new class of SiAlON-based ceramic composites for cutting tool applications. The effective properties of hybrid (TiCN/Co/hBN) functionally graded SiAlON-based composites are predicted using effective medium approximation and mean-field computational homogenization technique. Thermal conductivity, thermal expansion coefficient, elastic modulus, and fracture toughness are among the predicted properties. To get the optimal composite properties, attributes such as reinforcing volume fractions, particle sizes, layer numbers, layer material compositions, interfacial resistance, and porosity are considered. As a validation, FG SiAlON composite insert samples with tailored properties are developed using spark plasma sintering. The sintered samples are characterized to relate the microstructure with obtained properties.