Microstructure and tribological performance of an aluminium alloy based hybrid composite produced by friction stir processing

In this study, friction stir processing (FSP) was utilized to incorporate SiC and MoS2 particles into the matrix of an A356 Al alloy to form surface hybrid composite. A constant tool rotation rate of 1600 rpm and travel speed of 50 mm/min with a tool tilt angle of 3° was used. The wear resistance of the processed samples improved significantly as compared to that of the as-cast alloy. Microstructural analyses showed a uniform distribution of reinforcement particles inside the nugget zone, and a MoS2 rich mechanically mixed layer (MML) on the top of worn surface. This MoS2 layer is considered to stifle plastic deformation and thus, to improve tribological properties of the alloy.

Research highlights
► FSP was utilized to fabricate A356/SiC/MoS2 surface hybrid composite.
► FSP resulted in microstructural modification and uniform distribution of particles.
► The hybrid composite displayed higher hardness compared to the Al matrix alloy.
► A MoS2 rich layer on the top of worn surface decreased subsurface deformation degree.
► Wear resistance of hybrid composite improved as compared to the Al matrix alloy.