30%SiC_(p)/Al复合材料空间服役温度环境适应性研究

The adaptability of 30%SiC_(p)/Al composite materials to space service temperature environment

30%SiC_(p)/Al复合材料具有较高的比强度和比刚度,应用于火星车驱动组件需满足空间环境温度下的高强韧性和高尺寸稳定性需求。文章对粉末冶金法制备的铝基碳化硅复合材料开展了空间环境地面模拟试验,分别从力学性能、组织结构和热物理性能等方面对材料的大温域空间环境适应性进行系统分析。结果表明,材料的力学性能和热物理性能随温度呈现规律性的变化,且具有各向异性:低温条件下抗拉强度提高,线膨胀系数降低;高温条件下冲击韧性提高,导热系数降低;经高低温循环后残余应力降低,抗拉强度提高,线膨胀系数各向异性降低。在此基础上,初步分析了铝基碳化硅复合材料受不同空间温度环境影响,力学性能和热物理性能发生变化的内在机理。

When the 30%SiC_(p)/Al composite materials, with high specific strength and rigidity, are used in the Mars rover, the properties of high toughness and high dimensional stability in the space temperature environment should be considered. In this paper, the space environmental simulation tests are carried out for the aluminum-based silicon carbide composites prepared by the powder metallurgy, to evaluate their adaptability to the space environments in terms of mechanical properties, microstructure, and thermosphysical properties. It is shown that the mechanical properties and the thermo-physical properties vary regularly with the temperature and exhibit anisotropy. The tensile strength is increased and the linear expansion coefficient is decreased with the temperature at low temperature;the impact toughness is increased and the thermal conductivity is decreased with the temperature at high temperature. After the high & low temperature cycling test of the composites, the tensile strength increases, while the residual stress and the anisotropy of the linear expansion coefficient decreases. On this basis, the mechanism of the variations of the mechanical and the thermo-physical properties of the aluminum-based silicon carbide composites under space thermal environment is briefly analyzed.