Simultaneous synthesis and densification of α-Zr(N)/ZrB 2 composites by self-propagating high-temperature combustion under high nitrogen pressure

Abstract

Simultaneous synthesis and densification of α-Zr(N)/ZrB 2 composites from a 85 mol% Zr/15 mol% B mixed-powder compacts have been achieved by self-propagating high-temperature under a nitrogen pressure of 10 MPa. Composites consist of fine and short rodlike ZrB 2 grains (0.1 μm ϕ–0.5 μm l) dispersed into α-Zr(N) matrix (3 μm). Dense composite materials (96.5% of theoretical) exhibit excellent mechanical properties, in which their bending strength and H v are 560 MPa and 6.5 GPa, respectively. This bending strength is much superior to those (205 and 480 MPa) of dense equi-axial α-Zr(N) (10 μm) and dense ZrB 2 (6 μm). Fine and rodlike ZrB 2 grains greatly enhanced their mechanical properties.