An investigation of ceramic/aluminium composites as shields for hypervelocity impacts

The protection efficiency of single-shield bumpers made of composites based on the aluminum matrix containing the disperse ceramic inclusions of SiO2 or Al2O3 is considered for a Whipple-type shield. The aim of the paper is t o compare the protection efficiency of the first bumpers made of the metal composites with that for the duralumin shield by impact of spherical steel projectile with the velocity of 5.5 and 7.5 km/s. Mass fraction of the cera mic inclusions accounts for 15 and 30 percent of the total composite. A thi ck backwall plate was used, and the maximum depth of fragment craters on th e witness plate is taken as a protection characteristic of shields made of different materials: reference aluminum alloy, composites under study, and loosely-packed metal powder bumpers. The bumpers made of the metal composit es, Al-matrix plus embedded ceramic inclusions, are shown to have the poore r protection efficiency than those made of the duralumin alloy when used wi th steel impactors. It is shown that by impact of the hypervelocity steel p rojectile the shield material strength, if it is rather low bur not zero, m ay essentially affect the damage pattern of the backwall in spite of the hi gh level of realized impact pressures. (C) 1999 Elsevier Science Ltd. All r ights reserved.