Mg Alloy Particle-Reinforced Epoxy/Ti Alloy Lattice Interpenetrating Phase Composites: Preparation, Microstructure, Friction and Damping Properties

This study fabricated Mg alloy particle-reinforced epoxy/Ti alloy lattice interpenetrating phase composites (EP-Mg (p) /Ti (L) IPCs) via pressureless infiltration. Microstructural analysis reveals that Mg (p) are uniformly distributed within the EP, forming an effective rigid reinforcement network. The incorporation of Mg (p) induces a striking trade-off in dynamic properties: it mitigates the severe thermal softening typical of pure polymer matrices, maintaining a low coefficient of friction (COF ≈ 0.4) under high-load/high-speed conditions, while drastically reducing the loss factor (tan δ) from 0.489 to 0.051. Despite this damping reduction, compared to the bare Ti (L) , the tan δ of the EP-Mg (p) /Ti (L) IPCs is roughly 4.6 times higher, achieving an exceptional balance between high structural stiffness (storage modulus of 3883 MPa) and vibration attenuation. This performance evolution is dictated by a multiscale friction-damping mechanism. At the mesoscale, finite element method (FEM) simulations reveal that Mg (p) act as micro-scale load-bearing nodes. This rigid network maintains structural integrity to prevent bulk thermal runaway under severe frictional conditions, while simultaneously suppressing the primary interfacial micro-slip dissipation channel. Furthermore, the Mg (p) intrinsically “anchor” the polymer chains, restricting chain slippage and drastically reducing free volume. This dual constraint on “interfacial micro-slip” and “chain mobility” fundamentally shifts the macroscopic energy dissipation mechanism from flexible viscoelastic conversion to a dominant rigid elastic response.