STRUCTURE, MECHANICAL AND TRIBOLOGICAL PROPERTIES OF GLASS-TO-METAL COMPOSITES BASED ON IRON–CARBON ALLOYS

Abstract

Principle mechanical and tribological properties of glass-to-metal iron–carbon alloys with 5% glass modified with boron carbide, copper, and boron nitride additives are investigated. It is shown that the introduction of 2% boron carbide in the starting powder mixture provides a significant increase in the wear resistance and friction coefficient (0.27–0.42), compared to B₄C-free materials. The use of hot forging promotes a sharp increase in the wear resistance, compared to sintered materials, and hardly affects the friction coefficient. The microstructure of glass-to-metal sintered materials has a distinct heterophase character and consists of metallic matrix phase based on at least three types of grains (borocementite Fe₃ (B_0,7C_0,3), lamellar and grain pearlite) and a glass phase, which is distributed in a steel matrix in the form of either thin layer at the grain boundaries or separate inclusions of irregular shape up to 30–50 µm in size.