Effect of Post-Fabrication Heat Treatments on the Microstructure of WC-12Co Direct Energy Depositions

Laser-Directed Energy Deposition (L-DED) is an additive manufacturing technique that has lately been employed to deposit coatings of cemented carbides, such as WC-Co. During deposition, complex microstructural phenomena usually occur, strongly affecting the and mechanical behavior coatings. Post-fabrication heat treatments (PFHTs) may be applied homogenize strengthen microstructure; nevertheless, best authors’ knowledge, just a few papers deepened effect these on carbides fabricated by manufacturing. This work evaluates influence four PFHTs evolution hardness L-DED WC-12Co. For each treatment, different combinations solubilization time temperature (between 30 180 min from 400 °C 700 °C, respectively) were adopted. The microstructure was investigated optical scanning electron microscopy equipped with energy-dispersive spectroscopy, whereas properties determined Vickers measurements. Based results, high heterogeneity in terms WC particles, η-phase structures, Co distribution observed sample as-built condition. Some cracking defects also samples, irrespective treatment conditions. Finally, finer lower amount brittle ternary η-phase, together increase (1030 ± 95 HV10), found for highest dwelling times (180 min) temperatures range 500–600 °C.