• Nosko, Martin
• Lotfian, Saeid
• Azimi-Roeen, Ghasem
• Kashani-Bozorg, Seyed Farshid
• Orovcik, Lubomir

Abstract

<p>A mixture of pre-milled Fe₃O₄ and Al powder was added to the surface of an aluminum alloy 1050 substrate to obtain hybrid surface nanocomposites using friction stir processing. In situ nano-sized products were formed by the exothermic reaction of Al and Fe₃O₄. The reaction is triggered by hot working characteristics of the process. The microstructure and crystallographic microtexture transition and grain boundaries evolution of the fabricated nanocomposite were investigated using optical microscopy, X-ray diffraction, field emission scanning electron microscopy, and electron backscattered diffraction analyses. It is illustrated that matrix means grain size decreased in the specimens, which is processed without and with the introduction of the powder mixture to ∼8 and 2 μm, respectively. In addition, high angle grain boundaries showed marked increasing that demonstrates the happening of dynamic restoration phenomenon in the aluminum matrix. Moreover, the fraction of low ςCSL boundaries showed increasing (remarkably in the presence of hard particles); these boundaries play the main role in dynamic recrystallization. The incorporation of nano-sized products such as Al₁₃Fe₄ and Al₂O₃ in the dynamically recrystallized aluminum matrix produced a pre-dominantly Cube_Twin texture component induced by the stirring function of the rotating tool. As a result, the effect of nano-sized products is constrained.</p>

Topics

• nanocomposite
• impedance spectroscopy
• surface
• grain
• grain size
• grain boundary
• scanning electron microscopy
• x-ray diffraction
• aluminium
• positron annihilation lifetime spectroscopy
• Photoacoustic spectroscopy
• texture
• optical microscopy
• recrystallization