Effect of Mo Alloying on the Interfacial Bonding Strength and High-Stress Abrasive Wear Performance of Honeycomb TiCp/High-Chromium Cast Iron Composites

The honeycomb architecture of the titanium carbide particle (TiCp)-reinforced high-chromium cast iron (TiCp/HCCI) composites consists of TiCp-rich composite zones forming the honeycomb walls and TiCp-free HCCI matrix zones without intentionally added TiC particles. To mitigate the susceptibility of the composite-zone/matrix-zone interface to cracking under high-stress abrasive wear, Mo was introduced into TiCp preforms using ferromolybdenum (FeMo) powder to improve the interfacial bonding and wear resistance of honeycomb TiCp/high-chromium cast iron composites. The effects of FeMo addition (0, 10, 20, and 30 wt.%) on the composite-zone microstructure, interfacial shear strength, and high-stress abrasive wear behavior were investigated. Increasing FeMo addition promoted carbide enrichment and coarsening in the composite-zone matrix, and Mo2C formed at 30 wt.% FeMo. The Vickers hardness increased from 909.2 to 1151.7 HV, while the interfacial shear strength increased from 121.9 to 182.7 MPa. The volumetric wear rate decreased to a minimum of 0.639 × 10−3 cm3·min−1 at 20 wt.% FeMo, 37.4% lower than that of the FeMo-free composite, but increased by 11.3% at 30 wt.% FeMo. FeMo20 exhibited smaller surface height variations and less severe subsurface TiC damage, whereas FeMo30 showed more pronounced intraparticle TiC cracking and damage to the surrounding matrix. These results indicate that the wear performance is governed by the combined effects of composite-zone strengthening, interfacial load transfer, and the ability of TiC particles to maintain their integrity under cyclic abrasive loading.