New Chinese technology makes semi-solid aluminum alloy easier to form

Under the continuous support of the National 973 and 863 Programs and international cooperation projects, the Advanced Controlled Solidification Team of the National Nonferrous Metal Composite Engineering and Technology Research Center of Beijing Nonferrous Metal Research Institute mastered the basic principles of semisolid metal solidification process and invented spirals. The new technology of annular seam electromagnetic stirring solves the core technical problems of semi-solid aluminum alloy forming.

To make a metal material into a desired part, there is a process from melting to forming, and there is also a transition from liquid metal to solid metal. In the 1970s, it was discovered that metal materials cooled from the liquid to the solid state and that some of the solids first solidified out of the liquid. There was a transitional state of semi-liquid and semi-solid coexistence. This liquid-solid coexisting metal was called Semi-solid metal.

Semi-solid metal forming technology can theoretically be applied to most metals such as aluminum, magnesium, copper, steel, and metal matrix composites, but due to the different nature of various metal alloys, semi-solid metal pastes are prepared during the process. There will be different difficulties in the process. In spite of this, the technology is continuously being applied as a green, near-finishing new technology. Using this method, a high-strength aluminum alloy cast rod with a diameter of more than 300 mm can be prepared. At the same time, the technology has settled in Hunan Wenchang Technology Co., Ltd. and has built China's first semi-solid specialized production enterprise for wear-resistant aluminum alloy parts for vehicles. The products have already replaced imports, and the transformation of scientific and technological achievements into practical productivity has been realized.

At present, the technical team is using this technical principle to develop aluminum-based composite brake brake discs for subways and motor vehicles. Currently, this product can only be produced in Germany and Japan. After the research, the product has passed the assessment test of the China Academy of Railway Sciences. It is expected that China's subways and trains will be equipped with brake discs, a key component of domestic production.