Microstructural characterization and compression mechanical response of glass hollow spheres/Al syntactic foams with different Mg additions

Aluminum syntactic foams with different magnesium contents were fabricated by pressure infiltration of glass hollow spheres. Effect of Mg addition on microstructure, compression properties and corresponding deformation behavior as well as energy absorption under different strain rates loading was experimental investigated. Increasing Mg contents resulted in interface reactions between matrix and glass spheres forming MgAl₂O₄, Si and Mg₂Si hard phases, leading to the improvement of compression strength, structural stiffness and energy absorption capacity of syntactic foams, however, reducing the strain rate sensitivity of the syntactic foams. The addition of Mg content decreased the stress relaxation and load transfer ability of the matrix and developed the syntactic foam into severe brittle fracture during quasi-static compression. Nevertheless, the influence of Mg addition on the macroscopic compression deformation behavior of syntactic foams was weakened at increasing high strain rate loading.