Effect of nanosized particles on the bainitic transformation in austempered ductile irons

Abstract

Abstract The austempered ductile iron was austenitized at 900°C for 1 h and quenched in an isothermal quenching furnace at 380 °C, 0,5 h, 1 h, 2 h, 4 h, 6 h. This paper aims to investigate the effects of nanosized particles (50nm) of titanium carbite+titanium nitride (TiCN+TiN), titanium nitride (TiN) and cubic boron nitride (cBN) on the bainitic transformation in austempered ductile irons (ADI). The samples upper bainitic microstructure is studied by metallographic microscope (OM), X-ray diffractometer (XRD) and scanning electron microscope (SEM). The influence of the nanosized additives on the kinetic of the bainitic transformation and on the morphology of the bainitic structure is investigated. The abrasive wear testing and hardness measurements are carried out. It is established that the presence of nanoadditives in the bainitic cast irons leads to the changes in their microstructure which increases their abrasive wear resistance. The studied nanocomposite materials expand the potential for new ADI applications in the industry.