Laser-Driven Micro-Flyers for Dynamic Fragmentation Statistics of Boron Carbide

Abstract

Dynamic fragmentation through high-rate impact generates large numbers of fragments with various shapes and sizes. The fragmentation failure mode is an important part of the protection capacity of advanced ceramics which typically feature high strength and low density but fail in brittle modes. The penetration resistance of these brittle materials has been linked to the fragment size and shape created through impact in the literature [1]. Such studies have shown that particular fragment size and shape combinations can more effectively erode incoming projectiles, presenting a possible route to improve penetration resistance. These results stand in contrast to other studies that examine links between penetration resistance and material properties (e.g. fracture toughness or stiffness) which have sometimes resulted in contradictory correlations. Boron carbide has received a strong focus in the literature in recent years as an advanced ceramic with one of the highest specific strengths and lowest densities [2]. Yet boron carbide exhibits poor penetration resistance at higher loads, a phenomenon that some researchers attribute to a phase transformation termed “amorphization” [2]. To better understand the protection capacity of boron carbide under high rate loading, we use a laser-driven micro-flyer apparatus to impact boron carbide specimens.