| Abstract: | Results from emission electron microscope investigations of thermal and mechanical behaviour of the Laves-phase NbFe2 and of two-phase areas in the binary system Nb Fe are presented. The melting process of NbFe2 samples with included μ-phase NbFe was observed in the emission microscope and supported the existence of a eutectic between both intermetallic compounds. The Laves-phase NbFe2 was deformed plastically by a microhardness tester and also homogenously by a compressive device during electron microscope observations. Both yield stress and microhardness of NbFe2 were measured as a function of temperature up to 1550 K. The relation between a critical temperature T0 of the hardness-temperature curve and the melting temperature Tm was T0/Tm = 0,64, in good agreement with results from other Laves-phases. During the heating of NbFe2 samples a niobium oxide decoration structure appeared at residual air pressures from 1 · 10−6 torr to some 10−4 torr. The observed density of decoration points amounted to (1…5) · 108 cm−2. A discussion shows the possibility of a connection between decoration points and dislocations emerging from the crystal. |
