Hot forging Nb₄AlC₃ ceramics with enhanced properties

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·m^1/2), which was higher than that of untextured ceramics (6.88 MPa·m^1/2). 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).