Effects of addition of V a and VI a group elements on recrystallization and mechanical properties of hight purity aluminum

Abstract

The effects of addition of V, Nb, Ta, Cr, Mo and W individually in small amounts to aluminum of high purity were studied by means of hardness measurements, tensile tests and transmission electron microscopy.The results obtained were as follows:(1) The alloying elements had little effects in improving mechanical properties, softening temperature and micro-structure of aluminum, when they were added in the amounts within their solid solubility limits at the temperature of annealing.(2) Considerably great effects were given, when the alloying elements were added in the amounts beyond their solid solubility limits at the temperature of annealing. There were observed increase of tensile strength, elevation of softening temperature and other effects with the increase of alloying elements.It was shown by electron microscopy that the structures of the above specimens 50% cold worked and those during annealing after cold working were more complicated as compared with the structure of the paragraph (1).(3) Addition of chromium to aluminum was more effective than V, Nb, Ta, Mo and W in increasing tensile strength and elevating softening temperature. Hot hardness value of Al-0.41 at.%Cr alloy was little decreased with temperature up to 200°C. However, it was nearly three times as high as that of pure aluminum at 400°C.