The additive manufacturing technique performed via laser powder bed fusion has matured as a technology for manufacturing cemented carbide parts. The parts are built by additive consolidation of thin layers of a WC and Co mixture using a laser, depending on the power and scanning speed, making it possible to create small, complex parts with different geometries. NbC-based cermets, as the main phase, can replace WC-based cemented carbides for some applications. Issues related to the high costs and dependence on imports have made WC and Co powders emerge as critical raw materials. Furthermore, avoiding manufacturing workers’ health problems and occupational diseases is a positive advantage of replacing WC with NbC and alternative binder phases. This work used WC and NbC as the main carbides and three binders: 100% Ni, 100% Co, and 50Ni/50Co wt.%. For the flowability and spreadability of the powders of WC- and NbC-based alloy mixtures in the powder bed with high cohesiveness, it was necessary to build a vibrating container with a pneumatic turbine ranging from 460 to 520 Hz. Concurrently, compaction was promoted by a compacting system. The thin deposition layers of the mixtures were applied uniformly and were well distributed in the powder bed to minimize the defects and cracks during the direct sintering of the samples. The parameters of the L-PBF process varied, with laser scanning speeds from 25 to 125 mm.s^─1 and laser power from 50 to 125 W. Microstructural aspects and the properties obtained are presented and discussed, seeking to establish the relationships between the L-PBF process variables and compare them with the liquid phase sintering technique.

In Additive Manufacturing (AM) using the Laser Powder Bed Fusion (L-PBF) technique, spherical powders are the most commonly preferred for direct sintering. However, composites such as cemented carbides and heavy alloys often exhibit irregular shapes. Due to the requirement for extremely fine grain size, the cohesive behavior of the particle bed becomes significant, influencing its compressibility and porosity. These physical properties result in powders with coarse textures, which lead to low fluidity and interruptions in material flow within the ducts. This study evaluates the flowability of WC and W refractory materials combined with Co and Ni. Key interparticle properties, including real and bulk density, bulk compressibility and porosity, and granular shear, were analyzed to understand their influence on the deposition layer behavior in the powder bed. These parameters are crucial for understanding the micro-behavior of granular materials and correlating it with their macro-behavior. The rheological aspects of these composite powders are discussed, aiming to establish correlations between the manufacturing process and the resulting properties of their mixtures.

This work investigates the influence of surface contamination and milling media on the processing of WC–Co grinding sludge for extrusion-based additive manufacturing. Two industrial sludge batches were evaluated. Semi-quantitative EDS confirmed that both residues are rich in hardmetal-related elements, mainly W and Co, supporting their classification as WC–Co-based grinding sludge. Batch 1 was successfully processed by aqueous ball milling using PDADMAC as dispersant, whereas Batch 2 exhibited severe adhesion and agglomeration under the same conditions, preventing effective milling. Alternative non-aqueous milling media were therefore investigated. Isopropanol led to partial improvement, while kerosene enabled effective milling and produced a more homogeneous powder. SEM observations, FTIR spectra, and TGA results demonstrated that organic surface contaminants strongly influenced particle dispersion, liquid–particle affinity, and milling behavior. Capillary rheometry showed that PEG 8000-based feedstocks prepared from well-processed powders exhibited more suitable flow behavior for extrusion, although manual mixing introduced pressure fluctuations in Batch 2 feedstocks. Extrusion tests confirmed that kerosene milling restored the processability of Batch 2, enabling the production of coherent printed structures. In addition, sintered samples produced from Batch 1 displayed a microstructure characteristic of WC–Co cemented carbides, confirming the feasibility of converting grinding sludge into consolidated hardmetal-like materials. The results demonstrate that surface contamination and milling media are critical parameters for enabling the direct reuse of WC–Co grinding sludge in additive manufacturing.

Niobium-based refractory alloys have attracted attention in several industrial areas, such as metalworking, steelmaking, military, and armoring applications, among others. The production of these refractory alloys using additive manufacturing techniques, specifically selective laser fusion in a powder bed (L-PBF), has been a major challenge; this is primarily due to the complex optimization of the sintering process parameters required to obtain dense parts, free of porosity or cracks, and to achieve highly homogeneous layers in the powder bed. However, the success of L-PBF is highly dependent on the physical properties of the powders used in the process. Key factors such as good flowability, reduced particle size and narrow distribution, sphericity, and density influence powder spreading, powder layer uniformity, and the final part integrity. Furthermore, properties of the composite, such as hardness, toughness, and wear resistance, can be modified by changing the cermet composition, which could also negatively impact its flowability. This work aims to evaluate the physical properties of NbC-based cermets with different compositions to better understand their influence on metallic powder flowability. Optimizing powder properties and flowability through processing parameters is crucial for L-PBF to fully harness the potential of NbC-based cermets, thereby paving the way for their broader adoption in high-performance applications.