Enhanced mechanical properties and wear resistance of Al–Cu–Mg alloy fabricated by press-and-sinter processing

Abstract

Two of the main challenges facing the current application of press-and-sinter aluminium alloys are poor densification and insufficient properties such as mechanical properties and wear resistance. In this work, the press-and-sinter Al–4.4Cu–1.6Mg alloy (wt.%) and 5SiC/Al–4.4Cu–1.6Mg (wt.%) composite are successfully developed through optimizing the sintering temperature and heat treatment. The results show that the relative density, hardness and mechanical properties of as-sintered alloy and composite increase with the increase of the sintering temperature. Under the same sintering temperature, the relative density of the composite is comparable to that of the single alloy. When the sintering temperature is 596 °C, both the alloy and composite achieve full densification with a relative density of 99.7% and 99.3%, respectively. Consequently, their hardness and mechanical properties also achieve the optimal value. For the peak-aged state, the alloy exhibits a favourable combination of yield strength, ultimate tensile strength of 325.3 MPa and 394.0 MPa and fracture elongation of 3.8%. The addition of the SiC particles further enhances the yield strength and ultimate tensile strength of the peak-aged alloy to 375.0 MPa and 441.0 MPa, respectively. The wear rate of the peak-aged composite is comparable to that of the 45 steel and is less than half that of the peak-aged alloy due to the enhanced hardness and the stable wear protection provided by the SiC particles.