Microstructure and mechanical properties of Al–Fe in situ nanocomposite produced by friction stir processing

Friction stir processing (FSP) was applied to produce aluminum based nanocomposites from powder mixtures of Al–10 at%Fe. Billet of powder mixtures were prepared by the use of conventional press and sinter route. The sintered billet was then subjected to multiple passages of friction stir processing (FSP). This technique has combined hot working nature of FSP and exothermic reaction between Al and Fe. Transmission electron microscopy (TEM) showed that the second phase particles (∼100 nm in size) were distributed uniformly in the aluminum matrix. The particles were identified as Al13Fe4. Due to the fine dispersion of particles, the aluminum matrix has ultrafine-grained structure (∼1 μm). The composites produced are fully dense with enhanced modulus (91 GPa) and tensile strength (217 MPa).