Development of Al₃Ti and Al₃Zr intermetallic particulate reinforced aluminum alloy AA6061 in situ composites using friction stir processing

Graphical abstract: - Highlights: • In situ production of AA6061/Al₃Ti and AA6061/Al₃Zr DRAMCs. • Application of FSP to AA6061/Al₃Ti and AA6061/Al₃Zr DRAMCs. • FSP homogenized the distribution of Al₃Ti and Al₃Zr particles. • FSP reduced the size of Al₃Ti and Al₃Zr particles to nanoscale. • FSP enhanced hardness and wear properties. - Abstract: Aluminum rich intermetallic particles are potential reinforcements for discontinuously reinforced aluminum matrix composites (DRAMCs). The objective of the present work is to produce AA6061/Al₃Ti and AA6061/Al₃Zr composites using in situ casting technique and applying friction stir processing (FSP) to enhance the distribution and morphology of Al₃Ti and Al₃Zr particles. AA6061/Al₃Ti and AA6061/Al₃Zr DRAMCs were produced by the in situ reaction of inorganic salts K₂TiF₆ and K₂ZrF₆ with molten aluminum. The microstructure was observed using optical and scanning electron microscopy. AA6061/Al₃Ti DRAMC exhibited clusters of Al₃Ti particles while the segregation of needle shape Al₃Zr particles was observed in AA6061/Al₃Zr DRAMC. The prepared composites were subjected to FSP. Significant changes in the distribution and morphology of Al₃Ti and Al₃Zr particles were observed after FSP. The changes in microhardness and sliding wear behavior of AA6061/Al₃Ti and AA6061/Al₃Zr DRAMCs before and after FSP is detailed in this paper