Impact of laser irradiation on microstructure and phase development of tungsten carbide - cobalt

Kurzfassung

Previous studies on Laser Powder Bed Fusion of tungsten carbide-cobalt (WC-Co) revealed several defects in the laser molten microstructures. To analyze the defect formation mechanisms and the fundamental impact of laser energy input on phase development and microstructure of WC- Co, single-pulse and single-track analogy experiments are conducted. Conventional WC-Co is used as substrate. Variations in cobalt content and processing conditions are investigated. It is found that a single laser exposure can be enough to induce decomposition of microstructure, WC grain growth, formation of non-equilibrium phases and thermal cracking. Based on the results, defect formation mechanisms and countermeasures are discussed.