Impact testing of particle reinforced composite hardmetals

Difficult-to-machine materials rely on dependable cutting tools that have long service lifetimes. Tough coated hard particle based hardmetals are novel materials that make exceptional cutting tools. This is a hard particle reinforced composite hardmetal which has many advantages over conventional WC-Co cutting tools that have been favored by industry for over 80 years. Microstructural evaluations of press and sinter and hot-pressed parts show that either technique is capable of producing dense, high quality, and defect free parts. Understanding the composite microstructure helps in understanding the effects its microstructure has on fracture. Instrumented impact testing was used to show that composite hardmetals have an impact toughness which exceeds that of WC-Co of equal cobalt content by 26% due to complex crack interactions with the microstructure. The fracture toughening mechanism of crack deflection around core particles gives these composites additional toughness.