Formation Of AL۲O۳/Steel Nano-Composite Surface Layer OnMild Steel Using Friction Stir Processing

In this study, the almost new processing technique,friction stir processing (FSP) was employed to producenano-composite surface layers on mild steel. Nano-sizedAl۲O۳ particulates were introduced to the stir zone bymeans of a pre-made groove. A tungsten carbide toolwas used to plasticize the mild steel substrate. SPparameters such as tool rotation and substrate advancingspeeds were adjusted to mix Al۲O۳ particles with theplasticize matrix. Composite surface layers were formedcontaining clusters of Al۲O۳. Increasing the ratio of toolrotation to substrate advancing speed resulted inbreakdown of Al۲O۳ clusters. A Al۲O۳/steel nanocompositesurface layer with uniform dispersion ofnano-sized Al۲O۳ powder was achieved using a toolrotation and substrate advancing speed of ۱۱۲۰ rpm and۳۱.۵ mm/s, respectively. The nano-composite surfacelayer exhibited a micro hardness value about three timesmore than that of the as-received mild steel; this isattributed to the presence of hard Al۲O۳ ceramicreinforcements in a matrix of refined acicular-typeferrite.

کلیدواژه ها:

Friction Stir Processing ، Nano-composite ، Al۲O۳ ، Micro Hardness.