Effect of Quenching and Partitioning on Microstructure, Impact Toughness and Wear Resistance of a Gray Cast Iron

Resumo

© 2025 by the authors.This study investigates the influence of quenching and partitioning (Q&P) on the microstructure, hardness, wear resistance, and impact toughness of GG25 gray cast iron, in comparison with as-cast, quenched, quenched-and-tempered, and austempered conditions. Q&P treatment promotes a significant fraction of retained austenite, with carbon enrichment stabilizing the austenite at room temperature. Microstructural analysis reveals a multiphase matrix composed of partitioned martensite, bainitic ferrite and carbon-enriched retained austenite, while the morphology and distribution of graphite flakes remain unchanged. Mechanical testing shows that Q&P enhances impact toughness without substantial loss of hardness, achieving a balance not observed in conventional quenching and tempering treatments. Tribological evaluation indicates that wear resistance is slightly lower than quenched and tempered samples but superior to as-cast iron, with deformation of retained austenite and tribofilm formation influencing wear behavior. These results demonstrate that Q&P represents a promising route for developing gray cast irons with enhanced toughness and maintained hardness, suitable for components subjected to impact and wear loading.

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