轻型高强Al-Si/SiC复合材料反射镜的制备与性能

文章采用反应烧结工艺制备 Si/SiC 材料，然后通过真空扩散渗铝工艺制备了 Al-Si/SiC 复合材料。通过精确调控浸渗合金的铝浓度使制备的Al-Si/SiC复合材料具有可控的热膨胀系数，利用该工艺制备出热膨胀系数连续可调（4.6×10-6K-1~8.7×10-6K-1，0~40℃）的 Al-Si/SiC 复合材料，其力学性能优异，经检测密度为2.86g/cm3，弹性模量为236GPa，断裂韧性为6.1MPa＆#183;m1/2，可采用线切割、铣磨、钻孔、攻丝等手段加工，相比SiC陶瓷材料更易于高精度机械加工。扫描电子显微镜分析表明，制备的Al-Si/SiC复合材料均匀、致密，光学抛光后表面粗糙度均方根值达到1.017 nm。各项测试数据表明， Al-Si/SiC复合材料作为反射镜可以满足空间光学的应用。

Preparation and Performance of Lightweight High-strength Al-Si/SiC Composite Mirror

Si/SiC composites are prepared by reaction sintering,and then Al-Si/SiC composite materials are produced with the pressureless infiltration fabrication technology using the Si/SiC composites. The Al-Si/SiC composites which have continuously adjustable coefficient of thermal expansion （CTE） （4.6×10-6K-1~8.7×10-6K-1, 0~40℃） are provided through precise control of Al volume fraction in the Al-Si alloy. Results show that Al-Si/SiC composites possess low density （2.86g/cm3）, high elastic modulus （236GPa） and fracture toughness （6.1MPa＆#183;m1/2）. Compared with SiC ceramics, the Al-Si/SiC composites are easier to wire cutting, milling, drilling and threading. Scanning electron microscopy observation displays that the composites are homogeneous and dense without porosity. Their surface roughness reach 1.017 nm （RMS）. Results indicate that Al-Si/SiC composites as the mirror material can meet the space optics application.