Promoting the high load-carrying capability of Al–20 wt%Sn bearing alloys through creating nanocomposite structure by mechanical alloying

Mechanical alloying has been used to form nanocomposite in an Al–20 wt%Sn alloy to promote its sliding wear performance, in particular the high load-carrying capability. X-ray diffraction and scanning electron microscopy characterization reveal that the nanocomposite is a structure of nanoscaled Sn particles distributed homogeneously in nanocrystalline Al matrix with typical size of the both smaller than 100 nm. The dry sliding wear performance, in particular at higher load, of the alloys prepared by mechanical alloying increases significantly comparing with that obtained by conventional powder metallurgy, and the optimal one was obtained by sintered at 723 K. This is due to the formation of uniform tin oxide layer on worn surface and better strength of the nanocomposite alloys. The wear mechanism of mechanical alloyed Al–20 wt%Sn alloys changes from delamination under lower sintering temperature to plastic flow and work hardening under higher sintering temperature.