Laser powder bed fusion of WC-Ni cermets: microstructural, phase and mechanical studies

The study explores the processing and characterization of dense tungsten carbide (WC)–10 wt.% nickel (Ni) structures (WC-10Ni) built using laser powder bed fusion (LPBF). LPBF experimental trials were conducted at different combinations of process parameters based on central composite design to develop process maps. Three samples built at different laser energy densities (LED of 460, 381.7 and 300 J·m ⁻³) with a 10 wt.% high relative density (> 83.8%) were subjected to microstructural analysis, phase analysis, microhardness assessment, and abrasive wear testing. The characterizations focused on understanding the microstructure and mechanical behavior of LPBF-built WC-10Ni and developing a correlation between LED and material behavior. Higher LED resulted in keyhole porosity, while lower LED led to lack-of-fusion pores. The carbide particle size increased with LED, attributed to thermal cycling and coalescence during solidification. Higher LED also induced phase transformations, such as, the decomposition of WC into W ₂C and the oxidation of Ni. Microhardness testing showed that the WC phase reached 1650 HV1, while the Ni matrix reached 1011 HV1. The abrasive wear testing demonstrated mass loss of < 1%. Investigation of the wear scar resulted in the conclusion that the uniform distribution of WC particles in the Ni matrix contributed to this performance. The above studies indicate a positive correlation among relative density, hardness, and wear resistance. The study paves the way to understand the processing and material characteristics of LPBF-built WC-10Ni. Graphic abstract: (Figure presented.).