The Assessment of the Transversal Rupture Strength (TRS) and Hardness of WC-Co Specimens Made via Additive Manufacturing and Sinter-HIP

This study focuses on the preparation of fine-grained WC/Co composite powder using rolling ball milling and spray drying techniques. The cemented carbide composition achieved through low-pressure sintering technology was WC-10Co-0.5Cr3C2-1TaC-0.5Ru (wt.%). To study the effect of sintering temperature on the microstructure and mechanical properties of WC-10 wt.% cemented carbide, the microstructure and phase constituents of the material were analyzed using X-ray diffractometry and scanning electron microscopy. Additionally, the physical and mechanical properties of the material were examined. The results indicate that as the sintering temperature increased from 1390 °C to 1450 °C, the grain size of WC in the alloy increased, resulting in a slight decrease in hardness, an increase in fracture toughness, and the transverse fracture strength increasing first and then decreasing. The sintered hard alloy prepared at 1410 °C exhibited fewer pores and a uniform and fine grain size, reaching a density of 99.98%, a hardness of 91.8 HRA, a fracture strength of 3962 MPa, and a fracture toughness of 14.7 MPa⋅m1/2

Microstructure and Properties of Fine-Grained WC-10Co-0.5Cr3C2-1TaC-0.5Ru Prepared by Rolling Ball Milling and Low-Pressure Sintering

Huang,

Xiong,

Qin

et al. 2023

Effects of Sinter-HIP Temperature on Microstructure and Properties of WC–12Co Produced Using Binder Jetting

Goncharov,

Mariani,

De Gaudenzi

et al. 2024

This study investigates the influence of different sinter-HIP temperatures and binder saturation levels on the microstructure and properties of WC–12Co cemented carbide, produced using binder jetting. The sinter-HIP process was performed at 1400 °C, 1460 °C, and 1500 °C and binder saturation levels of 60% and 75% were selected during printing. The binder saturation proved to affect the repeatability of the manufacturing process and the sturdiness of the green models. The increase of the sintering temperature from 1400 °C to 1460 °C is correlated with an increase in the density. Nonetheless, a further raise in temperature to 1500 °C leads to significant grain coarsening without clear advantages in terms of porosity reduction. Both the transverse rupture strength and Vickers hardness increase when the sinter-HIP temperature rises from 1400 °C to 1460 °C, where the typical results for traditionally manufactured WC–12Co are met, with a comparable grain size. The transverse rupture strength and Vickers hardness then decrease for samples treated at 1500 °C. Finally, potential issues in the manufacturing process are identified and correlated with the defects in the final components.

Additive Manufacturing of Tungsten Carbide (WC)-Based Cemented Carbides and Niobium Carbide (NbC)-Based Cermets with High Binder Content via Laser Powder Bed Fusion

Miranda,

dos Santos,

Condotta

et al. 2024

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.