Mechanical properties and microstructure of directionally solidified Fe-4.25%C eutectic alloy

Abstract

An analysis of mechanical properties of directionally solidified Fe-4.25%C eutectic alloy and its microstructure and fracture mechanisms is presented. Tests were conducted for macro-samples made with different growth rates. Strength tests were performed with the use of micro-samples taken from different cross-sections of macro-samples. Fe-4.25%C eutectic alloy finds application mainly in construction of structures exposed to abrasion under significant compression loads. As specified by the metastable phase diagram, Fe–Fe3C, the white eutectic or austenitic (γ) iron carbide Fe3C can be formed. The type of obtained morphology depends mostly on the temperature gradient G, the chemical composition, and growth rate, which has a substantial impact on the morphology of the γ-Fe3C eutectic. As earlier tests have proven, interphase spacing λ decreases as grow rate v increases, which improves fine-graining of the alloy. We show that directional solidification with controlled growth rate improves mechanical properties of the Fe-4.25%C eutectic alloy, enabling its use as a structural element in a significantly expanded range of applications.