Multi-directional freeze-casting of interpenetrating phase composites with multi-aligned structure, nearly isotropy, high performance

Interpenetrating phase composites (IPCs) can combine the distinctive properties of two materials, and customized manufacturing processes are applied to design reinforced skeletons in IPCs. In this study, a porous ceramic featuring diverse structural regions with different direction-aligned pore channels is fabricated by multi-directional freeze-casting. The size of samples can be efficiently adjusted by controlling the size and amount of freezing sources. After infiltration, the resulting multi-directional freeze-casting ceramic/polymer composite (MFCC) has isotropic and satisfactory mechanical properties. Meanwhile, it remains lightweight and performs the highest specific strength (66.7 kN m/kg) and specific energy absorption (19.2 kJ/kg) among tested materials. The vertical-aligned structural regions are responsible for the robust strength, and horizontal-aligned regions prompt energy absorption capacity. Radial-aligned regions induce slant crack propagation and alignment shift between two regions leads to crack deflection, further enhancing energy absorption capacity. Additionally, the MFCC samples with different sizes or pore sizes, demonstrate isotropic thermal conductivity due to the multi-directional alignment of ceramic walls, which provide efficient thermal pathways across different directions. The MFCC and its structural design are promising for enhancing material performance, especially in applications where isotropic mechanical properties and thermal conductivity are important.