Dry Sliding Wear Behavior of Tempered (T4 and T6) Hypereutectic Aluminum Alloy-Based Composites

The present work describes the effect of tempering (T4 and T6) processes on the dry sliding wear properties of ilmenite reinforced aluminum alloy (LM30) composites, prepared through stir casting route. In this process the composites were heated to 540 degrees C for 0.5-2 h followed by water quenching. Then the samples were first given (a) T4 treatment (natural ageing at room temperature), and in second case (b) T6 treatment (aged at 180 and 250 degrees C for 4 h before air cooling). Optical microscopy revealed the homogeneous distribution of ilmenite particles and redistributed silicon around the ilmenite in the alloy matrix. Rockwell hardness values suggested the superiority of T6 treated composite samples as compared to T4 treated and untreated samples due to enhanced precipitation of intermetallic compounds viz. Al13Fe4, FeSn2, FeTiSi, and Al3Ti. Similarly, superior wear resistance (against steel disc) of T6 treated composite samples was also observed. A responsible mechanism has also been established with the help of scanning electron microscopy of worn surface and wear debris. Finally, a comparative study revealed the excellent (similar to 4.0%) wear resistance (against EN31 steel disc) of T6 treated composite sample as compared to grey cast iron (traditional material) for brake drum applications.