Fatigue properties of SiC graded ceramic lattice structures with a triply periodic minimal surface manufactured by laser powder bed fusion

SiC graded ceramic lattice structure (GCLS) offers superior mechanical strength and its impact on fatigue warrants investigation. In this work, SiC triply periodic minimal surface (TPMS) GCLSs were prepared via laser powder bed fusion technology and liquid silicon infiltration process, alongside SiC TPMS uniform ceramic lattice structure (UCLS) as a reference. Fatigue properties, fatigue failure, and strengthening mechanisms were systematically investigated through compression fatigue tests, finite element (FE) simulations, and theoretical analysis. Fatigue failures of SiC UCLSs and GCLSs are influenced by cyclic ratcheting and fatigue damage, with cyclic ratcheting dominance. The fatigue strength ratios of UCLS and GCLS are 0.7 and 0.74, indicating that GCLSs exhibit stronger deformation resistance and superior fatigue performance. FE results show that surface tensile stress level in GCLS is lower than in UCLS, resulting in slower fatigue crack initiation. Stress redistribution and higher crack thresholds contribute to enhanced fatigue resistance in SiC TPMS GCLSs.