Niobium Carbide-Reinforced Ferrous Matrix Composites: An in situ Powder Metallurgy Approach

This study focuses on developing a new processing route for ferrous matrix composites reinforced with niobium carbide by producing the reinforcement particles in situ using powder metallurgy. The aim is to improve the interfacial adhesion between matrix and reinforcement compared to traditional ex situ methods. Computational thermodynamics and kinetic analysis were used to optimize the raw materials and processing parameters. The raw materials are mixed, uniaxially pressed, and sintered in a tubular furnace. The study finds that liquid phase sintering improves densification but also leads to clustering, niobium-free regions, and abnormal grain growth. The optimal combination of porosity and microhardness is 16.5 ± 0.7% and 952 ± 82 HV0.05, respectively. Although there is room for further adjustments in processing, this study lays the groundwork for creating valuable materials using Brazilian strategic raw materials and technology.