Boosting fracture toughness in (LAS) glass-ceramics via homogeneous electrospun nanofibers and fiber pull-out

Lithium aluminosilicate (LAS) glass-ceramics are widely recognized for their low thermal expansion, good chemical stability, and favorable mechanical strength. However, their inherent low fracture toughness restricts applications in high-performance components. To address this, we propose a homogeneous fiber-toughening strategy by incorporating structurally compatible LiAlSi 2 O 6 nanofibers as a well-dispersed reinforcing phase to enhance the performance of LAS glass-ceramics. LiAlSi 2 O 6 gel fibers were successfully prepared via sol-gel-assisted electrospinning, based on the formation of Si-O-C covalent bonds between PVA and polysilicic acid. And it was found that under the optimized conditions of a PVA content of 10 wt%, a heating rate of 1 °C/min, and a sintering temperature of 850 °C, the well-dispersed and high density nanofibers could be obtained. By introducing 5 wt% of this fiber into the LAS sol-gel powder, the composite materials were successfully prepared through hot-pressing sintering, and the influence of sintering temperature on their mechanical properties was systematically studied. The composite containing 5 wt% fibers sintered at 950 °C (Z4) exhibited the optimal combination of mechanical performance, with a flexural strength of 167±8.29 MPa, a fracture toughness of 4.46±0.15 MPa·m 1 / 2 , and a Vickers hardness of 9.3±0.48 GPa. Notably, the fracture toughness was enhanced by 44% compared to the fiber-free baseline. This significant enhancement is attributed to the strong interfacial bonding between the fibers and the matrix, combined with the fiber pull-out mechanism. The developed homogeneous fiber-toughening strategy proves highly effective for achieving high-performance LAS glass-ceramics.