Fabrication and wear characterization of an A413/Ni surface metal matrix composite fabricated via friction stir processing

Abstract

Abstract In the present study, friction stir processing (FSP) was used for the incorporation of Ni particles into the surface of an A413 alloy to fabricate a surface composite. FSP parameters were the rotation speed of 2000 rpm, the traverse speed of 8 mm/min and the tilt angle of 2°. Single pass and three-pass FSP were conducted on the samples. For the evaluation of microstructures, optical microscopy and scanning electron microscope were utilized. Also, for the investigation of intermetallic formation, energy dispersive spectroscopy was used. The wear resistance of different composites was investigated at ambient and elevated temperatures. Microstructural observations revealed that the FSP led to significant breakup of acicular Si particles, elimination of α­Al dendrites and heal the casting porosity. It was found that the hardness and wear behavior of A413 cast alloy were strongly influenced by applying FSP. Also, the in situ formation of Al3Ni particles during FSP was a critical factor controlling the wear mechanism. Sliding wear tests revealed that the increase in the number of passes created a homogeneous distribution of Al3Ni intermetallic particles and thereby resulting in a significant improvement in wear resistance at both room and high temperatures.