Tribological behaviour and wear mechanism of ADI with different hardness values

The tribological behaviour and wear mechanism of austempered ductile iron (ADI) with different hardness values were investigated. Results showed that the wear resistance of ADI was sensitive to hardness and service conditions. Under mild wear conditions, the low-hardness ADI sample exhibited high wear resistance because graphite was easy to transfer to the tribosurface and acted as a lubricant to reduce the friction coefficient. However, the high-hardness ADI sample was hard to deform plastically, which restricted the transfer of graphite from the matrix to the tribosurface. Under severe wear conditions, the plastic deformation of the low-hardness ADI sample gave rise to abrasive wear, which resulted in poor wear resistance. With the deterioration of wear conditions, the wear mechanism of ADI was transformed from micro-cutting wear to oxidative wear.