A Novel Ultrastable and Electromachinable Lithium aluminosilicate/TiC Composite

Novel lithium aluminosilicate/titanium carbide composites were developed to achieve near-zero thermal expansion and electrical discharge machinability (EDM). The approach involved combining a negative thermal expansion phase (β-eucryptite) with a positive thermal expansion reinforcing phase (nTiC). The β-eucryptite matrix was synthesized from kaolin and lithium carbonate and subsequently mixed with different nTiC volume fractions using high-energy dispersion. Materials were sintered by spark plasma sintering, optimizing the processing parameters to obtain full densification while avoiding liquid phase formation. The influence of composition on dimensional stability, mechanical performance, and electrical behavior was evaluated. The composite containing 22 vol.% TiC exhibited a coefficient of thermal expansion below 0.3 × 10 -6 K -1 . In addition, the material showed mechanical strength, elastic modulus, and hardness values of more than 155 MPa, 135 GPa, and 8 GPa, respectively. Electrical conductivity for EDM processing was achieved, demonstrating the feasibility of machining complex shape components from these ultra-stable composites.