Effect of Cr:Fe ratio on the mechanical properties of (Cr,Fe)7C3 ternary carbides in abrasion-resistant white cast irons

Abstract (Cr,Fe) 7 C 3 ternary carbides constitute the majority of eutectic in abrasion-resistant white cast irons. Density functional theory models have predicted these to a combination metallic, covalent and ionic bonding, proportions depending on carbide’s Cr:Fe ratio. However, experimental research validate predictions has been lacking. This study investigates characteristics as function ratio, which was manipulated from Fe-rich Cr-rich by varying Cr:C ratio bulk alloy. The carbides’ crystalline structure, hardness, Young’s modulus, fracture toughness abrasion performance assessed through techniques including nano-indentation, HR-TEM inner circumference test (ICAT). M formed at very low found an orthorhombic crystal structure. In all other alloys, with ratios above 2.7, hexagonal Hardness, modulus calculated increase (Fe 5 ,Cr 2 )C up maximum for (Cr 4 ,Fe (in 18Cr–6.8Cr:C WCI). gave highest hardness (22.9 GPa) (315 GPa), but also (4.5 MPa.m0.5). peak carbide composition this is consistent prediction DFT literature; while same shows marginal deviation predictions. Abrasion generally increased toughness, one exception: 4.3 2.7 . Although showed marginally lower inherent than 4.0 3.0 , higher imparted performance, associated modified morphology.