Die-cast multicomponent near-eutectic and hypoeutectic Al–Si–Ni–Fe–Mn alloys: Microstructures and mechanical properties

Abstract

Copyright © 2023 The Authors. Microstructures and mechanical properties of near-eutectic and hypoeutectic Al–Si–Ni–Fe–Mn alloys were studied under as-cast condition. Near-eutectic 78Al15Si4Ni2.5Fe0.5Mn (wt.%) and hypoeutectic 83.6Al11Si3Ni1.9Fe0.5Mn (wt.%) alloys were processed by high pressure die casting. These two alloys have the same ternary eutectic mixture of α-Al, Si and Al6(FeNiMn) with a melting point of 567 °C. Primary intermetallic phases of block-like Al17(FeNiMn)4Si and plate-like Al4(FeNiMn)Si2 in these two alloys were observed. Precipitates of Si and Ni-contained phase coexist in primary α-Al grains of hypoeutectic alloy. The lattice parameters of Al6(FeNiMn), Al17(FeNiMn)4Si, and Al4(FeNiMn)Si2 phases are slightly changed compared with orthorhombic Al3Ni, orthorhombic Al5.6Fe2 and tetragonal FeAl3Si2 phases from the database, respectively. These two alloys have excellent mechanical properties at high temperatures. The ultimate tensile strength (UTS) at 300 °C ranges from 135 ± 6 MPa (hypoeutectic alloy) to 157 ± 6 MPa (near-eutectic alloy), which is superior to commercial A383 alloy and some other heat-resistant alloys. Therefore, these near-eutectic and hypoeutectic Al–Si–Ni–Fe–Mn alloys have huge potential for industrial application at elevated temperatures.