Vol. 25, No. 3 (2026), Mat26864 https://doi.org/10.24275/rmiq/Mat26864

Influence of niobium on the microstructure, hardness, wear and impact resistance of austempered ductile iron

 

Authors

C.Y. Becerra-Mayorga, M. Vargas-Ramírez, E. Cardoso-Legorreta, F. Hernández-Santiago

Abstract

This study investigates the effect of niobium additions on the microstructure, wear resistance, hardness, and impact toughness of austempered ductile iron (ADI). Austempering treatments were performed at 250 °C and 300 °C for 15, 30, 60, and 90 min. The highest retained high-carbon austenite fraction (42.79%) was obtained in the alloy containing 0.3 wt.% Nb austempered at 250 °C for 60 min. The maximum hardness value (40.36 HRC) was achieved in the 0.3 wt.% Nb alloy austempered at 250 °C for 15 min. Regarding wear behavior, the lowest volume loss (1.35 mm³) was recorded for the 0.3 wt.% Nb alloy austempered at 250 °C for 15 min, indicating superior wear resistance under these conditions. The results show that niobium additions influence the microstructural evolution and mechanical performance of ADI, promoting higher retained austenite fractions and improved wear resistance under selected austempering conditions.

Keywords

Austempered, High carbon austenite, austempered ductile iron, niobium.

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