Research Highlights
Through the development of high-throughput materials, a group headed by professor Xuanhui Qu has optimized the composition and process of Cu-based composites through powder metallurgy, significantly increasing their friction and wear properties. While maintaining a stable friction coefficient, the wear loss of the material itself can be decreased and the displacement of the brake pads can be prevented. Owing to the characteristic lubrication performance and moisture absorption of high-quality graphite with a specific porosity, a tribo-film is formed during braking, which decreases the surface temperature and stabilizes the friction coefficient. In collaboration with Beijing Tianyishangjia New Material Corp., Ltd., brake pads consisting of such material have been manufactured and successfully applied to the China high-speed train series Fuxing, which operates at 350 km/h. The product won the PM Product Award at World PM2018.
Based on powder rheoforming, the group headed by professor Xuanhui Qu has established a systematic theory and techniques for the powder injection molding of special materials such as metal tungsten and aluminum nitride, thus solving the issues in the processing of such materials. An aluminum nitride frame with high thermal conductivity has been developed and has found application in integrated navigation systems for large surface vessels in China, solving the major problem of the previous frame that used materials with a low thermal conductivity leading to circuit overheating and navigation system failure under strong dynamic conditions. This has played a key role in ensuring the precise take-off and landing of carrier-borne aircraft. This achievement also won first prize of the China Nonferrous Metals Industry Science & Technology Invention Award. A tungsten electrode has also been developed and applied to the nuclear weapon trigger switch used by China, providing a final solution to a previously fatal defect, namely, the utilization of traditional tungsten and copper processing techniques resulting in residual copper that may lead to a premature switch failure and spurious triggering. The resistance to electron bombardment of the electrode was increased by a magnitude of two, substantially improving the reliability of the trigger switch. This achievement won first prize of the Science & Technology Development Award of the Ministry of Education in 2018.