碳纤维增强热塑性复合材料超声波焊接研究进展

碳纤维增强热塑性复合材料（Carbon fiber reinforced thermoplastic composite，CFRTP）由于其优越的力学性能、较低的加工成本及可回收性，逐渐成为继铝合金、高强钢之后的新一代轻量化材料。国内外科研机构和材料企业都投入巨资和人力竞相开展相关研究，部分高校、企业已开始探索将CFRTP应用于机身与车身的制造与装配。超声波焊接是最适合焊接热塑性材料的方法之一，也是实现大规模装配CFRTP零部件的关键使能技术之一。从CFRTP超声波焊接基本过程、接头形式、数值模拟、质量监控和异种材料连接五个方面进行分析，系统讨论CFRTP超声波焊接最新研究成果，展望CFRTP超声波焊接中有待解决的共性问题，以期为CFRTP零部件的大规模装配应用提供参考。

Advances in Ultrasonic Welding of Carbon Fiber Reinforced Thermoplastic Composites

In recent years, the application of chemical vapor deposition(CVD) single crystal diamond in the field of electronics has attracted attention, thanks to the progress of CVD single crystal diamond in growth technology and semiconductor doping technology. All along, the mature substrate processing technology is the basis for the application of semiconductor materials. Among them, ultra-precision polishing is the final process of wafer substrate processing, which directly determines the surface roughness and subsurface damage. It is foreseeable that the ultra-precision polishing plays an important role in the fabrication of high-quality diamond substrate. The polishing methods of single-crystal diamond at home and abroad in recent years are reviewed, with the goal of preparing large-sized and high-quality single-crystal diamond substrates, and analyzes from the aspects of processing equipment, process parameters, processing accuracy, processing efficiency and material removal mechanism. The advantages and disadvantages of various polishing methods are summarized, and the future development trend of polishing technology for large-size single crystal diamond substrates is prospected. At present, there are few surveys on the polishing technology of large-size single crystal diamond. Reference materials for domestic scholars are provided to carry out research on single crystal diamond polishing.