In situ experimental study on fracture toughness and damage mechanism of TiB₂‐reinforced steel matrix composites

Abstract

It is crucial to obtain better fracture property of particle‐reinforced metal matrix composites (PRMMCs) for application in structural parts. In this study, three‐point bending tests are conducted on a TiB2‐reinforced steel matrix composites (SMCs) with 9% and 13% TiB2 volume fractions to understand the effect of hot rolling and particle content on fracture toughness. Results show that increasing particle content has a negative effect on the fracture toughness of SCMs as a whole. Many microcracks induced by large‐size particle fracture initiate in the front of crack tip and coalesce with one another are observed, thus accelerating the main crack propagation. However, hot rolling can effectively improve the fracture toughness and hardness of SMCs with two particle contents. Particle characteristics and matrix plasticity of the SMCs are optimized by hot rolling, which finally enhances the crack propagation resistance. The present work provides guiding suggestions for effectively improving fracture properties of PRMMCs.