DEVELOPMENT OF NANOSTRUCTURED ALMIGSALLOYS

Aluminum and its alloys have a wide application in aerospace industry, because of their high specific strength, lightweight and corrosion resistance. Among aluminum alloys, Al6061 has maximum elongation. But it has minimum hardness among the most widely used aluminum alloys. In this study, nanostructured Al6061 alloy was prepared from elemental powders by mechanical alloying and heat treatment. 98.4% aluminum, 1% magnesium, 0.6% silicon powders were mixed and mechanically alloyed under argon atmosphere. The rotation speed of 500rpm and ball to powder ratio of 10:1 was employed. The mechanical alloyed powder was isothermally heat treated at 400 C for 2 h under argon atmosphere. The as milled and annealed powder was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that after 10h of milling, a solid solution of Al-Mg-Si with a grain size of ~ 40 nm was produced. MgSiparticles precipitate from solid solution during subsequent annealing. The as milled powder appeared to have good thermal stability against grain growth so that the grain size after annealing remained constant (~ 40 nm).

کلیدواژه ها:

elemental powder mechanical alloying nanostructure ، Al6061