B4C-Al基复合材料的空间碎片超高速撞击防护应用研究

Investigation on Shielding Application of B4C-Al based Composite for Hypervelocity Impact of Space Debris

摘要:

为了提高航天器在应对空间碎片超高速撞击时的防护能力,本文采用无压预烧和真空渗铝工艺制备了B₄C-Al基复合材料,并制作了B₄C-Al缓冲屏的Whipple式空间碎片防护构型,利用超高速弹道靶在3 km/s ~ 6.5 km/s的撞击速度范围内对B₄C-Al缓冲屏和典型铝合金缓冲屏开展超高速撞击实验。通过比较不同撞击速度下的缓冲屏穿孔特征、后墙损伤特征、碎片云结构等,结合SEM微观损伤形貌和EDS元素分布模式分析,重点阐述了不同缓冲屏材料特性对超高速撞击碎片云形成以及后墙撞击损伤之间的作用关系。研究表明,B₄C-Al缓冲屏可以更为有效破碎超高速撞击弹丸甚至使弹丸碎片熔化,同时基体中的金属增韧相又能保证缓冲屏整体结构不发生破坏。碎片云颗粒细化以及碎片云前端动能集中效应的缓解是B₄C-Al缓冲屏获得更佳防护性能的直接原因,初步研究结果为B₄C-Al基复合材料的空间碎片防护应用提供了一定的理论和技术支撑。

Abstract:

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 vacuum were designed as the front bumper of Whipple shielding configuration, and the hypervelocity impact tests were carried out on a hypervelocity impact range to evaluate the shielding performance of B₄C-Al bumper and Al alloy bumper under the impact velocity of 3 km/s ~ 6.5 km/s. By comparising the bumper penetration, the rear wall damage state and the debris clould structure of the two different bumper materials under various impact velocity 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 research results indicated that the B₄C-Al bumper can break the projectile into smaller pieces and even make the debris melt, and the impact damage of debris cloud on rear wall was 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 to obtain higher shielding capability of B₄C-Al bumper. This primary investigation provided theoretical and technical instructions for the design and application of B₄C-Al based composite materials in space debris shielding configuration.