INVESTIGATION OF THE FEATURES OF THE FORMATION OF THE STRUCTURE OF THE ALLOY Fe 55 % wt. Ga

Abstract

Possibilities of obtaining Fe-Ga alloy with a composition close to equiatomic by powder metallurgy have been investigated. Peculiarities of structure and phase formation in the Fe-Ga system in the conditions of sintering of a mixture of sprayed iron powder ПЖР 2.200.26 2.200.26 and cast gallium brand GL-1 at a mass ratio of components of 45:55, respectively, in a neutral medium (high purity argon) at temperature 1300 ^oC for 2 hours. It was found that despite the relatively low sintering temperature and short isothermal holding, the structure of the powder alloy is close to equilibrium, in contrast to cast alloys, which, according to numerous literature data, require several weeks of exposure to equilibrium. It is probable that the acceleration of physicochemical processes of alloying is due to the use of powder metallurgy methods. It was determined that the alloy structure consists mainly of large and dispersed, probably secondary crystals, the composition of the central part of which is close to the composition of the intermetallic Fe₃Ga₄, and the peripheral zones - to the intermetallic Fe₆Ga₅. It was determined that the microhardness of these crystals, ranges from 4 to 7 MPa. In the structure of the obtained alloy, a number of ultrafine crystals with a composition close to the composition of the intermetallic Fe₃Ga were also found. The variable composition of intermetallics that make up the structure of the obtained alloy is probably due to the peculiarities of the kinetics of phase transformations in this system under nonequilibrium conditions.