The Structure and Phase Composition Acquired by Fe–Ti–Ni–C Alloys in Thermal Synthesis

• Published in: Powder metallurgy and metal ceramics Vol. 59; no. 3-4; pp. 171 - 178
• Main Authors: Bagliuk, G.A., Maksimova, G.A., Mamonova, A.A., Goncharuk, D.A.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.07.2020; Springer; Springer Nature B.V
• Subjects: Alloys; Carbides; Cemented carbides; Cementite; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Glass; Grain size; Hardness; Hot forging; Hot pressing; Intermetallic compounds; Iron carbides; Iron compounds; Materials Science; Metallic Materials; Microhardness; Natural Materials; Nickel; Phase composition; Powders; Protective coatings; Sintering; Sintering (powder metallurgy); Solid solutions; Specialty metals industry; Stoichiometry; Synthesis; Titanium carbide; Wear resistance; hardness; stoichiometry; phase composition; metal matrix composite; titanium carbide; thermal synthesis; reinforced steel; intermetallic compound; structure
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-020-00149-2

The structure and phase composition of Fe–Ti–Ni–C alloys produced in situ by thermal synthesis at 1200°C using TiH 2 , Fe, graphite, and Ni powder mixtures have been studied. The synthesized alloys represent a skeleton of titanium carbide grains of different stoichiometry, with sizes varying from 0.5 to 16 μm, surrounded by metal reinforcement layers. The starting mixtures without nickel or with 5% Ni have coarse TiC grains. When Ni content of the mixture increases to 10–20%, the maximum grain size sharply decreases to 6–7 μm. The microhardness of the synthesized alloys decreases when nickel amount in the mixture increases to 15% but becomes somewhat higher at 20% Ni. The phase composition of the alloys substantially depends on the amounts of starting mixture components and includes titanium carbide, Fe 3 C cementite, α-iron solid solution, and intermetallic FeNi 3 (for ironcontaining mixtures) and Ni 3 Ti and Ni 4 Ti (for nickel-containing mixtures). When Ni content of the starting mixture increases to 10–20%, the lattice parameter and stoichiometry of TiC x slightly decrease and carbide particles noticeably refine. The thermally synthesized alloys have been ground to produce reinforced steel composite powders, which can find extensive application in depositing wear-resistant coatings and fabricating bulky parts by compaction followed by sintering, hot pressing, or hot forging.