Syntactic Aluminum Foam from Recycled Sawing Chips

A method for the reuse of aluminum (alloy 5754) sawing chips as a starting material for manufacturing aluminum matrix syntactic foams by powder metallurgy is described. In the tested samples, spherical Ni-superalloy hollow particles were used to increase the closed porosity of specimens up to 50 wt.%. Spark plasma sintering was used to consolidate the specimens. Only the sample with 30% hollow particles showed a clear maximum corresponding to a compression strength of 130 MPa. For all the samples, the plateau stress was over 120 MPa. The densification strain was over 40%, reaching 61% for the sample containing 30% hollow particles. All the samples showed high energy absorption capabilities and good absorption efficiency.