Microstructure and mechanical properties of Al–Si–X alloys fabricated by gas atomization and extrusion process

Abstract

In order to develop good wear resistant and high-strength alloys, Al 81Si 19 alloy was reinforced with transition elements such as Ni and Ce. The solubility of Si in aluminum was amplified, with increasing the Ni and Ce content in the rapidly solidified powders. The extruded bars consist of homogeneously dispersed fine Si particles along with Al 3Ni and Al 3Ce compounds (30–120 nm) in aluminum matrix (grain size below 500 nm). The tensile strength at room temperature for Al 81Si 19, Al 78Si 19Ni 2Ce 0.5 and Al 76Si 19Ni 4Ce 1 bars extruded at 400 °C was estimated as 281, 521, and 668 MPa, respectively. In addition, the maximum tensile strength of 730 MPa was attained in Al 73Si 19Ni 7Ce 1 bulk alloy. The uniform dispersion of precipitates (Si, Al 3Ni and Al 3Ce particles) from the supersaturated Al matrix of ternary and quaternary alloys after extrusion was effective for enhanced mechanical properties.