Experimental and numerical study of creep properties of aluminum syntactic foams

Aluminum syntactic foams with densities of 1.4-1.6 g/cm(3) exhibit exceptionally high compressive creep resistance up to 500 degrees C. Their creep behavior is characterized by a short primary-like regime, followed by a long secondary-like behavior, where the strain rate is minimum, and, at high stresses, a ternary-like behavior. The minimum strain rate varies with stress according to an apparent stress exponent, which takes a value of unity for stresses below 9 MPa, and a value of 14 above 9 MPa. Finite-element modelling provides predictions that are in semi-quantitative agreement with these results.