Metallic microlattice and epoxy interpenetrating phase composites: Experimental and simulation studies on superior mechanical properties and their mechanisms

Selective laser melting fabricated microlattices and epoxy interpenetrating phase composites are presented in this work. Composites showed strengths up to 360, 65 and 20% higher than its constituent lattice, bulk epoxy and lattice of equivalent density respectively. Superior strength enhancements up by 40% higher than the linear addition of constituent two phases were measured for the composites. Mechanisms were found to derive from the higher energy required for the uniform deformation of reinforced struts as opposed to the buckling of freestanding, consistent with our design principles. A decoupling also exists for strength and densification mechanisms; as such, composites hold large plateau strains up to -0.66 strain at a high strength of 140 MPa and 21.6% relative density, resulting in improved specific energy absorption capabilities up by 560% to 46 J/g. The design space of the composite is also fully elucidated by simulation models.