Fabrication of dense nano-laminated tungsten carbide materials doped with Cr3C2/VC through two-step sintering

Abstract This work investigates the critical roles of two-step sintering (TSS) and laminated structure on the sintering behavior and mechanical properties of functionally graded WC-TiC-Al 2 O 3 nanostructured composite materials doped with Cr 3 C 2 /VC. Results show that excellent mechanical properties are achieved for tailored TSS conditions with a hardness of 27.91 ± 2.3 GPa and a flexural strength of 1423.3 ± 23.5 MPa. The desirable mechanical properties are attributed to the suppressed grain growth without densification deterioration. TSS is more effective in facilitating the favorable dispersion of secondary phase toughening nano-particulates in a WC matrix than conventional sintering (CS). Cr 3 C 2 /VC dopant plays an important role in maximizing and shifting the temperature range of the kinetic window for WC-Al 2 O 3 composites. Al 2 O 3 crack deflection, transgranular Al 2 O 3 , microcracking, WC crack bridging and plate-like WC crack deflection are the major toughening mechanisms. Residual surface compressive stress induced by the graded structure is also an appreciated contribution to the improvement of mechanical properties.