Study On High Strength Cast Aluminum Alloy Applied To High-speed Train

High-speed train is the developing trend of railway transportation in china, of which weight reduction is one of the key techniques of High-speed train. Nowadays in our country, most materials used in the parts of trains are made of iron and steel, which make the train have high weight, and limit the development of high-speed train. Therefore, it is of great theoretical and practical significance to explore new lighter material to take the place of current steel material.Aluminum alloy is the optimum material for weight reduction. However, the properties of presently existing cast aluminum alloys can not meet the requirements of the key parts of High-speed train. And their casting technique is easy to make more foundry defects. A new cast aluminum alloy is developed in this paper. Mg and Zn are the main elements of the alloy. Preparation technique and heat treatment technology are also investigated. The result shows that the tensile strength is 400 MPa and the elongation is 10.1%; the alloy has better pourability than Al-Cu series alloy and has slight thermal cracking tendency; second-class heat treatment is adopted ,which makes the best solution strength; the phase of T(Al2 Mg3 Zn3)exists at the grain boundary in the reticular form as cast, while after being heat treated most of it dissolve in the basal body; element Mn change needle-like Al3Fe into stick-like state, and the addition of rare earth elements better its shape further; to improve the density of cast is one of good strengthening methods of aluminum alloy, with which the strength of ZL101 is improved by 51% as cast; porosity can also be used to check the feeding passage blocked or not.