On the Microstructure and Wear Behavior of Fe‐Based/B₄C Composite Coating Processed by Vacuum Cladding

Abstract

To increase the service life of mechanical parts under severe wear environment, composite coatings with wear resistance are required. Fe‐based/B4C composite coating is fabricated on the surface of ASTM 1045 steel by vacuum cladding and the microstructure, hardness, and wear behavior of the coating are investigated. The results show that the coating is mainly composed of the coating matrix of α‐Fe, [Fe, Ni] solid solution, and the strengthening phases of eutectic borides M2B and carboborides M23(C, B)6 with irregular block distribution. The dispersion strengthening and solution strengthening of the coating microstructures improve the overall hardness distribution of the coating, the microhardness, and macrohardness of the coating are greatly improved, which are better than that of quenched and tempered ASTM 1045 steel (QT45 steel) and NM400 steel. The results of abrasive wear test under different loads (130 N/45 N) indicate that wear scar of the coating become shorter and shallower due to the antiabrasive grinding effect of strengthening phases, and wear resistance is significantly greater than that of QT45 steel and NM400 steel. The main wear mechanisms associate with QT45 steel and NM400 steel involve plastic deformation and microcutting, whereas the coating is mainly a mix mode of plastic cutting and fatigue spalling.