Analysis of abrasive impact wear of a bimetal composite using a newly designed wear testing rig

Abstract

In this study, the abrasive impact wear behaviour of a bimetal composite made of MMSs and LCSs (Mn8/SS400) were investigated by comparison with the existing wear resistant steels (benchmark steels) using a newly designed wear testing rig. The parameters including wear loss, wear rate, and hardness were evaluated. Scanning electron microscopy (SEM), X-ray diffractometer (XRD), and electron backscatter diffraction (EBSD) were used to analyse the wear mechanisms. The wear resistance of Mn8/SS400 bimetal composite is up to 2.8 times higher than that of benchmark steels due to better work hardening sensitivity of the bimetal composite. After 300 h abrasive impact wear, the highest microhardness of the subsurface layer for Mn8 reaches 601.31 HV, which is much greater than that of matrix (292.24 HV), showing a remarkable work hardening effect. The wear mechanism of Mn8/SS400 bimetal composite is ascribed to synergistic effect of grain refinement strengthening, dislocation strengthening, and twin strengthening. Prior to the 200-h abrasive impact wear test, the dominant wear mechanism in the Mn8/SS400 bimetal composite is primarily attributed to twin strengthening. However, following the 300-h impact wear test, the contribution to wear resistance becomes increasingly significant from all three strengthening mechanisms (dislocation, grain refinement, and twin strengthening).