Nanoscale Abrasive Wear of CoCrMo in In Situ TEM Sliding

The mechanical behaviour of materials at nanometre dimensions has been a major recent topic of research. In this study, the wear properties of a similar to 60-nm thin foil made of the ductile fcc phase of a CoCrMo alloy were examined using in situ sliding test in a transmission electron microscope by sliding a silicon AFM tip on the fcc matrix under an applied normal load of 416-1,279 nN. The material near the surface was deformed plastically, forming dislocations and dislocation cells at the surface. The wear process was found to be strongly dependent on extrinsic factors, namely the attack angle between the tip and the CoCrMo surface. At an attack angle of 64 degrees, the surface was removed by continuous fractures 40-73 nm below the surface. At a lower attack angle of 24 degrees, the abrasive wear switched to ploughing.