Microstructure and properties of in-situ Al–Si/Al 2 O 3 composites prepared by displacement reaction

Abstract

In this work, we have studied the displacement reaction of Al and SiO₂ powder blends by mechanical alloying (MA) for 20 h and low-temperature sintering. The microstructural evolution of powder and compacted specimens were studied by X-ray diffraction and scanning electron microscopy. The extent of the milling on the displacement reaction was studied by differential thermal analysis (DTA). The results show that the reaction between Al–SiO₂ couple does not initiate after milling up to 20 h but occurs after thermal treatment of powders. DTA results indicate a lowering in the reaction temperature of Al–SiO₂ couple after milling. Following the DTA results, we densified the Al–SiO₂ powder compacts at 700°C to produce an in-situ Al–Si/Al₂O₃ composite. The physical, mechanical, and tribological performance of the composite at different milling times are also reported here.