Novel dynamic compressive and ballistic properties in 7075Al+SiC+B4C hybrid composite

Abstract

When ceramic-reinforced metal-alloy-matrix hybrid composites are fabricated by a liquid-pressing process, excellent protective capabilities against ballistic impacts can be achieved in armored structures and materials applications. In this study, a hybrid 7075-T6 Al matrix composite reinforced with SiC and B 4 C particulates (SiC p or B 4 C p ) was fabricated to increase the volume fraction of reinforcements and the resultant dynamic and ballistic properties, and was compared with monolithic composites reinforced with SiC p or B 4 C p . Quasi-static and dynamic compressive properties were evaluated by operating a universal testing machine and a split Hopkinson pressure bar at strain rates of 10 -3 s -1 and 2800 s -1 , respectively. SiC p s and B 4 C p s were homogeneously distributed in the Al matrix, while ceramic/matrix interfaces were well bonded without SiC p or B 4 C p agglomerations, pores, or cracks, and the volume fraction of ceramic reinforcements reached 57 vol.%. In the hybrid composite, fine SiC p and finer B 4 C p (size; 10 micro m and 5 micro m) worked for the synergic strengthening by increasing the total reinforcement fraction, and three fracture phenomena such as Al matrix deformation, cracking of ceramic reinforcements, and ceramic/matrix interfacial debonding were well homogenized, thereby leading to the excellent strength/ductility combination along with very high strain energy density and consequently to the great improvement of ballistic performance.