Employing friction stir processing technique for fabricating steel/TiC nano-composite surface layer on carbon steel

In this study, the almost new processing technique, friction stir processing (FSP) was employed to produce nano-composite surface layers on mild steel. Nano-sized TiC particulates were introduced to the stir zone by means of apre-made groove. A tungsten carbide tool was used to plasticize the mild steel substrate. SP parameters such as tool rotation and substrate advancing speeds were adjusted to mix TiC particles with the plasticize matrix. Composite surface layers were formed containing clusters of TiC. Increasing the ratio of tool rotation to substrate advancing speed resulted in breakdown of TiC clusters. A TiC/steel nano-composite surface layer with uniform dispersion of nano-sized TiC powder was achieved using a tool rotation and substrate advancing speed of 1120 rpm and 31.5 mm/s, respectively. The nanocomposite surface layer exhibited a micro hardness value about three times more than that of the as-received mild steel; this is attributed to the presence of hard TiC ceramic reinforcements in a matrix of refined acicular-type ferrite.

Keywords:

Friction Stir Processing , Nano-composite , TiC , Micro Hardness