Honcharuk D. Regularities of the influence of gallium doping on the formation of the structure and properties of sintered materials of functional purpose based on Fe and Al

Honcharuk D. A. Regularities of the influence of gallium doping on the formation of the structure and properties of sintered materials of functional purpose based on Fe and Al. Qualification scientific work in the form of a manuscript. Dissertation for the degree of Candidate of Technical Sciences in the specialty 05.16.06 "Powder Metallurgy and Composite Materials" (13 Mechanical Engineering). – Institute of Problems of Materials Science named after I. M. Frantsevich NAS of Ukraine, Kyiv, 2025. The dissertation is devoted to solving a scientific and technical problem – the study of phase and structural transformations in the systems Fe Ga and Fe Ga Al and the development of powder magnetostrictive materials based on them with an optimal set of magnetic, mechanical and anti-corrosion characteristics.The features of phase and structure formation in powder materials of the Fe - Ga, Al - Ga and Fe - Al - Ga systems were studied and the competing influence of Al and Ga on the structure and phase formation of materials Fe - (17…22) wt.% (Ga + Al) was investigated. The influence of alloying impurities Ni and Ga on the processes of thermal synthesis in the Fe - (Ti - C) and Fe - (Ti - В4С) systems was studied and an increase in corrosion resistance was found with simultaneous alloying of them with B and Ga.The influence of Al and borides, nitrides and carbides of titanium on the characteristics of elasticity and strength of materials of the Fe - Ga system under compression and bending conditions was studied. The greatest strengthening effect was found in the material of the composition (Fe - 21.4Ga) 5 vol.% TiB2, for which the elastic limit is about 1000 MPa, and the strength approaches 1500 MPa. A research stand has been developed to record the dependences of magnetic induction in ferromagnetic materials on the strength of the external magnetic field. It has been established that the materials Fe - 22.5 wt. % Ga, (Fe - 22.5 wt. % Ga) + 5% vol.% (TiB2; TiC; TiN) and Fe - 19.3 wt.%Ga - 1.75 wt.% Al have magnetostriction above 210, 180…150 and above 130 ppm, respectively. These indicators exceed the level of industrial magnetostrictive materials based on Fe, doped with Ni, Co, V, Mo, Cr (50…100 ppm) and powder alloys Fe - 22 wt. % Ga (80…150 ppm). The developed powder materials have advantages over cast Fe - Ga materials, since the required shape and thickness of the products can be obtained already at the stage of compaction of the mixtures.