Effect of ZrC nanopowder addition in WC preforms on microstructure and properties of W–ZrC composites prepared by the displacive compensation of porosity (DCP) method

Abstract

In the present work, WC preforms with varied amounts of ZrC nanopowder (0–3.5 vol.%) were prepared using gel-casting base on nontoxic sodium alginate and then reactively infiltrated by molten Zr2Cu through displacive compensation of porosity method. The influence of ZrC nanopowder addition on the relative density, phase composition, microstructure, and properties of the final composites were investigated. The relative density, Vickers hardness, and flexural strength of the resulted composites prepared by reactive infiltration first increased and then decreased with increasing fraction of ZrC nanopowder in WC preforms. When the added fraction of ZrC nanopowder was 1.5 vol.%, the relative density, hardness, and flexural strength of the resulted composite reached their maximum values of about 97.3± 1%, 10.9± 0.3 GPa, and 503± 3 MPa, respectively. Fractography studies revealed that the fracture mode of composites was predominately intergranular. The W-ZrC composite was ablated by an oxyacetylene flame for 60 s. The mean value of mass and linear ablation rates of the composite were 2.1 ± 0.1 mg/s and 2.9 ± 0.3 μm/s, respectively. W-ZrC composites fabricated in complex and near net shapes at modest temperature and at ambient pressure by a reactive infiltration process can be utilized in aerospace applications.