Hot forging Nb4AlC3 ceramics with enhanced properties

Abstract

Textured Nb4AlC3 ceramics were rapidly and efficiently prepared by hot forging through spark plasma sintering (SPS). The longitudinal compression ratio of textured Nb4AlC3 ceramics was −78.3%, and the lateral expansion ratio was 32.1%. The grains grew preferentially along the direction perpendicular to the c-axis, forming the texture microstructure. The Lotgering orientation factor f(00l) was calculated to be 0.63. The thermal conductivity of textured Nb4AlC3 ceramics along the c-axis direction (11.23 W·m−1·K−1) (25 ℃) was lower than that of untextured ceramics (13.75 W·m−1·K−1) (25 ℃). The electrical conductivity perpendicular to the c-axis direction reached 4.37×106 S·m−1 at room temperature. The ordered layered grains increased the resistance of crack propagation, resulting in a higher fracture toughness parallel to the c-axis direction (9.41 MPa·m1/2), which was higher than that of untextured ceramics (6.88 MPa·m1/2). The Vickers hardness tested at 10 N on the texture top surface (7.18 GPa) was higher than that on the texture side surface (6.45 GPa).

Keywords

• nb4alc3
• texture
• anisotropy
• microstructure
• properties