Low sliding-wear resistance of ultrafine-grained Al alloys and steel having undergone severe plastic deformation

Dry sliding wear characteristics of ultrafine-grained Al alloys 1100, 5052, and low carbon ferrite-martensite dual phase steel (Fe-0.15C-0.25Si-1.11Mn-0.06V) were investigated. The Al alloys and the steel were processed by the accumulative roll bonding and the equal channel angular pressing, respectively, to produce the ultrafine-grained microstructure. Pin-on-disk wear tests were performed on the alloys at various applied loads at room temperature. Hardness and strength of the ultrafine-grained alloys increased with the increase in the accumulated total plastic strain. However, wear resistance of the ultrafine-grained alloys was not improved after the severe deformation. The low wear-resistance of the ultrafine-grained alloys was attributed to the lack of strain hardening due to unstable and non-equilibrium grain boundaries of the alloys and the cracking at the interface of the ferrite and martensite phases.