Materials & design

In order to improve the survivability of in-orbit spacecraft against the hypervelocity impact (HVI) of space debris, the lightweight B4C/Al composite is fabricated by the pressureless presintering and Al infiltration in vacuum and applied as the bumper of Whipple shield configuration. The HVI tests ranging from 3 km/s to 6.5 km/s are carried out to assess the shield performance of B4C/Al bumper. The fitting line of the ballistic limit for the B4C/Al bumper is obtained, and its critical projectile size can be improved by about 20% in comparison to the conventional Al alloy Whipple shield configuration. Based on the damage features of bumper and rear wall, the B4C ceramic phase of B4C/Al composite is the key reason to break the projectile into smaller fragments or liquid droplets of debris cloud. The Al plastic phase with three-dimensional network enhances the toughness of B4C/Al composite bumper, which plays an important role in avoiding structural failure caused by shock waves. Hence, the impact kinetic energy of debris cloud is obviously dispersed, and the subsequent impact damages on real wall are alleviated accordingly. The primary investigation provided theoretical and technical instructions for the design and application of B4C/Al composite in MMOD shield configuration. Keywords: B4C/Al composites, MMOD, Hypervelocity impact, Damage behavior, Shield performance

Hypervelocity impact damage behavior of B4C/Al composite for MMOD shielding application