Структурa і властивості матеріалів Fe—Al—Ga в області концентрацій, збагачених залізом

Abstract

The structure and mechanical properties of materials of the Fe—Al—Ga system (in the concentration range of 78—82% (wt.) Fe), obtained by sintering at 1150 oC in Ar medium for 1 hour, were studied. The starting materials were mixtures of Fe, Al powders and crushed Fe—Ga ligature alloy of equiatomic composition. Seven mixtures were produced, of which two mixtures had a binare compo¬sition (% (wt.)): Fe—17,5Al and Fe—21,4Ga; and all the others were three-component, with gradual substitution of Al for Ga. The phase composition of the samples was studied by the methods of X-ray diffraction and local X-ray microspectral analyses. To determine the mechanical characteristics, the Brinell method was used, microdurometric studies were carried out, and mechanical tests of the samples were carried out under conditions of uniaxial compression. The effect of Al on the change in the porosity of Fe—Al—Ga ternary alloys and the maximum manifestation of the “swelling” effect for Fe—Al composition samples was established. It is shown that the main phase of the obtained materials is a solid solution based on Fe, in which Al and Ga are dissolved in the appropriate proportions. In the Fe—Al samples and in the samples of the ternary composition, there are local separations of phases containing, in addition to the main metals, carbon and oxygen in significant quantities. In the structure of Fe—Ga samples, carbon is not detected, and oxygen is present in a small amount. The results of the mechanical compression tests showed that the Fe—21,4Ga composition samples, like the pure Fe samples, are quite plastic and do not break up to a degree of compression of 75—82%. For materials with binary composition with Ga, an increase in the elastic range was recorded compared to pure Fe, and the replacement of a small proportion of Ga with Al (up to 2% by weight) in the material composition contributes to its strengthening. Keywords: Fe, Al, Ga, microstructure, phase formation, microhardness, mechanical compression characteristics.