MECHANICAL PROPERTIES AND IN-SITU DIFFRACTION STRAIN MEASUREMENTS IN ALUMINUM-MULLITE MICROSPHERE SYNTACTIC FOAMS PRODUCED BY LIQUID METAL INFILTRATION

摘要

High-strength aluminum syntactic foams are fabricated using a liquid metal infiltration technique. Unalloyed and 7075 aluminum are infiltrated into a packed bed of hollow mullite-ceramic spheres. The resulting syntactic foams have relative densities between 0.45 and 0.60 (1.25 -1.65 g/cm~3).High compressive strengths are observed (100 -250 MPa), with exceptional energy absorption exceeding 50 MJ/m~3 during densification. In-situ measurements of lattice strains within the mullite phase within the mullite phase during compressive loading are performed using high-energy synchrotron x-rays, permitting investigation of sphere stresses and foam damage evolution during loading.