The Use of Nb in Aluminium Alloys and Composites

F. AUDEBERT; M. GALANO; F. SAPORITI; X. JIANG; M. CAVALIERE

Turin

Congreso; XX International Symposium on Metastable, Amorphous and Nanostructured Materials; 2013

Aluminum is the second largest metals used in the world. Its lightweight and good combination of properties allows it to be used in several industrial sectors. The worldwide requirements for reducing the energy consumption and pollution have increased the demand of new and high performance lightweight materials. Thus, the development of nanostructured Al-based alloys and composites is a key direction to solve this demand. High energy prices and decreased availability of some alloying elements open the opportunity to use no conventional elements to be used in Al alloys and composites. Then, Nb is one of these elements that can be used to develop new Al alloys and composites. In the present work Nb has been investigated as an alloying element for producing high corrosion resistance amorphous alloys and high strength nanoquasicrystalline alloys to be used at elevated temperature. Nb stabilizes icosahedral order in the liquid state which allowing retains amorphous or quasicrystalline phases by rapid solidification. The local order and stability of rapid solidified Al alloys containing Nb were studied. Rapid solidified samples were produced by means of melt spinning and gas atomization. Extruded bars were also produced from atomized powders and their microstructure was characterized by means of X-ray diffraction, scanning and transmission electron microscopy and calorimetric techniques. The mechanical properties were studied and compared with the current available commercial Al alloys. On other hand, it is also explored the use the Nb as reinforcement to produce new Al alloy matrix composites. Extruded bars and rolled samples were produced. The microstructure was characterized and the mechanical properties were measured. The influence of processing conditions on the microstructure and properties are discussed. Nb has been found to be an excellent alloying element that can enhance strength and toughness of some rapid solidified Al alloys and composites.