Effect of single and hybrid hollow sphere reinforcement on the deformation mechanism of aluminum matrix syntactic foam at a low strain rate

The combination of soft matrix alloys and brittle spheres has gained unceasing demand due to its structural strength and tailored properties to meet industrial and commercial needs. Single sphere aluminum matrix syntactic foams (AMSFs) show poor ductility and fracture strength at high volume fractions of reinforcement. In the present investigation, three different volume fractions of the single sphere (alumina hollow spheres and cenospheres), syntactic foams (SF) and hybrid SF were prepared using a powder metallurgy route with a maximum reinforcement fraction of 30%. The lowest density of 2.17 g cm -3 was produced with no chemical reaction observed between matrix and reinforcement. The quasi-static compression studies have shown a significant effect of particle size and volume fraction with respective mechanical properties (peak stress = 601 MPa (Sample #1), 610 MPa (Sample #4) and 525 MPa (Sample #10)). The densification strain, energy absorption, energy absorption efficiency (EAE) and ideal EAE have been predicated for all the samples. The macroscopic deformation of SFs is in good agreement with stress-strain data. The results show that the slope of the plateau region follows a negative linear trend against the strain hardening exponent. (c) 2021 Elsevier B.V. All rights reserved.