Hot forging Nb 4AlC 3 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 °C) was lower than that of untextured ceramics (13.75 W·m^-1·K^-1) (25 °C). The electrical conductivity perpendicular to c-axis direction reached 4.37 × 10⁶ S/m at room temperature. The ordered layered grains increased the resistance of crack propagation, resulting in a higher fracture toughness parallel to 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 (TTS) (7.18 GPa) was higher than that on the texture side surface (TSS) (6.45 GPa).