Shielding Application of B4C-Al based Composites for Hypervelocity Impact of Space Debris

In order to improve the shielding ability of spacecraft against space debris hypervelocity impact, the B4C-Al based composites prepared by pressureless presintering and aluminium infiltration in a vacuum were designed as the front bumper with Whipple shielding configuration, and the hypervelocity impact tests were carried out to evaluate the shielding performance of B4C-Al bumper and Al alloy bumper at the impact velocity of 3 similar to 6.5 km/s. By comparing the bumper penetration, the rear wall damage state and the debris cloud structure of two different bumper materials at various impact velocities as well as the SEM and EDS results, the relationship among the bumper material properties, the cratering mechanics of rear wall and the debris cloud characteristics was discussed. The results indicate that the B4C-Al bumper can break the projectile into smaller pieces and even melt the debris, and the impact damage of debris cloud on rear wall is alleviated significantly. Meanwhile, the good toughness of Al metallic phase can keep this bumper structure intact. Hence, both the pulverized small debris and the decreased impact kinetic concentration of debris cloud are the main reasons for obtaining a higher shielding capability of B4C-Al bumper. This primary investigation provides theoretical and technical instruction for the design and application of B4C-Al based composite materials in space debris shielding configuration.