Fabrication of in situ Al-Ni surface composite on 2024 aluminum alloy by friction stir processing

In this research, in situ Al-Ni surface composite produced on 2024 aluminum alloy using friction stir processing (FSP). FSP performed at a tool rotating rate of 1250 rpm and travel speed of 24 mm/min with and without nickel powder. Metallographic images show that the grain size after FSP has reached about 30% of primary metal grain size. With the addition of nickel powder, intermetallic compound of Al3Ni is formed in situ. Micro-Vickers test demonstrates that the reinforcement particles (Ni) have uniform distribution near the surface of primary metal. After FSP, primary metal hardness of about 54 vickers reached to in its maximum value of 120 vickers and 129 vickers in stir zone without and with addition of nickel powder, respectively. The results show that the fabrication of in situ composite using FSP has improved the wear resistance of the primary metal.