Fabrication and Microstructure Characterization of in situ formed ZrB2 and TiB2 particles on AA6061 metal matrix composites

Abstract

- In-situ fabrication of aluminum matrix composites (AMCs) has gathered widespread attention of researchers due to inherent advantages over ex-situ methods. Aluminum alloy AA6061 reinforced with various amounts (0, 2, 4 and 6 wt. %) of ZrB₂ and TiB₂ particles were prepared by the in-situ reaction of inorganic salts such as K₂ZrF₆, K₂TiF₆ and KBF₄ to molten aluminum. X-ray diffraction patterns of the prepared AMCs clearly revealed the formation of ZrB₂ and TiB₂ particles without the presence of any other intermetallic compounds. The in-situ formed ZrB₂ and TiB₂ particles significantly refined the microstructure and enhanced the mechanical properties of AA6061 alloy. The weight percentage of ZrB₂ and TiB₂ was varied from 0 to 9 in steps of 3.The microstructures of the in-situ AMC were studied using Scanning Electron Microscope (SEM) andoptical microscopy. The form ation of ZrB₂ and TiB₂ particles in the matrix enhanced the microhardness and ultimate tensile strength of the AMCs.