Investigations on Microstructure and Properties of 16 wt% Cr-3 wt% B-0.6 wt% C-1 wt% Mn-Fe Alloy

In this paper, a wear-resistant alloy with the chemical composition of 16 wt% Cr-3 wt% B-0.6 wt% C-1 wt% Mn-Fe, in which M2B was the antifriction skeleton, was prepared in a medium-frequency induction furnace. The microstructure and mechanical properties were experimentally investigated. The results show that the microstructure of the Fe-Cr-B alloy was composed of lath martensite and clavate, reticular, and clustering borides (M2B). After the thermal treatment, the morphology, chemical composition, and volume fraction of the M2B did not change significantly. Because of the reduction in element saturation, secondary borides M-23(B,C)(6) precipitated from the matrix, which resulted in a decrease in matrix microhardness. As a result, the bulk hardness and abrasive resistance of the alloy accordingly decreased, and the impact toughness inversely increased. According to the results of XRD, electronic probe microanalyzer (EPMA), and TEM, the chemical formula of M2B was FeCr0.89Mn0.14(B,C), which resulted in a body-centered tetragonal (BCT) structure. The chemical formula of the M-23(B,C)(6) was Fe17.97Cr4.13Mn1.14 (B,C)(6), which resulted in a face-centered cubic (FCC) structure.