Composite design and property assessment of high and medium entropy layers in TaCHfCZrCTiCVC/HfB₂ZrB₂TiB₂ system

This research investigates the impact of carbonous and metallic additives on the microstructure of high entropy carbide (HEC) and medium entropy in-situ boride (ME-ISB) composite layers. The HEC layer, made from TaCHfCZrCTiCVC with Gr and Si additives, and the ME-ISB layer, composed of HfO 2 ZrO 2 TiO 2 with nano carbon black (C.B n ) and B 4 C, were consolidated using spark plasma sintering (SPS) at 2000 °C under 40 MPa for 10 min. Bulk density was measured via the Archimedes method, and microstructural analysis was conducted using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The findings revealed that the HEC layer has a higher sinterability (99.7%) compared to the ME-ISB layer (78.4%). Hardness tests showed the HEC layer (≈ 15 GPa) is significantly harder than the ME-ISB layer (≈ 1.2 GPa), with average grain sizes of 430 ± 150 nm for HEC and 200 ± 100 nm for ME-ISB.