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Al–Si–Cu–Mg cast aluminum alloys have important applications in automobile lightweight due to their advantages such as high strength-to-weight ratio, good heat resistance and excellent casting performance. With the increasing demand for strength and toughness of automotive parts, the development of high strength and toughness Al–Si–Cu–Mg cast aluminum alloys is one of the effective measures to promote the application of cast aluminum alloys in the automotive industry. In this paper, the research progress of improving the strength and toughness of Al–Si–Cu–Mg cast aluminum alloys was described from the aspects of multi-component alloying and heat treatment based on the strengthening mechanism of Al–Si–Cu–Mg cast aluminum alloys. Finally, the development prospects of automotive lightweight Al–Si–Cu–Mg cast aluminum alloys is presented. [ABSTRACT FROM AUTHOR]

In recent years, degradable Zn alloys have received wide attention as new biomedical materials. This paper mainly studied the microstructure, mechanical properties and in vitro degradation properties of Zn- x Fe (x = 0, 0.5, 1, 1.5, 2 wt%) alloys which prepared by stirring casting method. The results showed that the FeZn 13 phase was produced in Zn Fe alloys. The FeZn 13 phase distributed in the matrix and played the role of grain refinement and second phase strengthening, which improved the hardness and ultimate tensile strength (UTS) of Zn Fe alloys. Compared with pure Zn, the hardness and UTS of the Zn-1.5Fe alloy increased by 156.9% and 86.6% respectively, indicating that the mechanical properties of Zn Fe alloys were improved significantly. With the increase of Fe content, the self-corrosion potential of Zn Fe alloys decreased and the self-corrosion current increased, which means that the degradation rate was accelerated. The immersion test showed that the degradation rate of Zn 2Fe was increased by 62.0% compared with that of pure Zn. Moreover, the degradation rate was higher at the initial stage of the immersion test than that of the later stage. • Zn-Fe alloys were prepared by an environmentally friendly method. • The hardness and ultimate tensile strength (UTS) of Zn-Fe alloys have been improved. • The degradation rate of Zn-Fe alloys was accelerated to meet biomaterial degradation standards. [ABSTRACT FROM AUTHOR]

The mechanical properties of Al–Si–Mg alloys are largely related to eutectic Si, intermetallics and pores. In this study, the effects of the Sc addition on the eutectic Si, Sc containing precipitates and pores were investigated, and the mechanical properties of the alloy were improved by adding Sc. The Sc addition leads to the formation of Al 3 M (M = Sc, Zr, Ti,V) and reduction of pore size, increasing the yield strength (YTS), ultimate tensile strength (UTS) and elongation (EL) of the alloy after the T6 heat treatment. The formation of thermally stable Al 3 M (M = Sc, Zr, Ti,V) after the T6 heat treatment improves the elevated temperature strength. [Display omitted] [ABSTRACT FROM AUTHOR]

It is well known that the addition of Sc and Ag to Al alloys can promote the nucleation of α-Al grains and θ′-Al 2 Cu precipitates. In this study, the effects of Sc and Ag on grain size and precipitates, as well as the contribution of grain refinement and precipitation strengthening to yield strength of Al–Cu alloys were quantitatively characterized. The addition of Sc refines the grain size and θ′ precipitate, resulting in the yield strength, ultimate tensile strength and elongation of Al–Cu alloy increasing to 314.2 MPa, 410.6 MPa and 6.31%, respectively. The addition of Ag increases the number density and volume fraction of Ω precipitate, resulting in the contribution of Ω precipitate to the yield strength increasing to 204.8 MPa, and the yield strength, ultimate tensile strength and elongation of Al–Cu alloy reaching 430.0 MPa, 449.9 MPa and 3.60%, respectively. The elastic modulus of AlCuMnMgTiAg alloy is increased to 73 GPa. [ABSTRACT FROM AUTHOR]

• The evolution of 3D morphology of eutectic Si was characterized by deep corrosion method. • Effect of Sc on the nucleation and growth of eutectic Si in Al-Si-Mg alloys was quantified by in situ observation. • X-ray tomography (X-CT) showed the evolution of 3D morphology of pores in Al-Si-Mg alloys. [Display omitted] The mechanical performance of Al-Si-Mg cast alloys is highly dependent on the pore size and morphology of eutectic Si, which is especially critical for high fatigue life components. Many studies have shown the linear relationship between them. However, it is unknown how the beneficial alloying elements for grain refinements and precipitation strengthening will have an impact on those critical properties. In this study, we used synchrotron X-ray to quantify the kinetics of eutectic Si growth for three alloys. These eutectic Si nucleate and grow rapidly at the initial stage of growth, and then the morphology tends to remain unchanged. Surprisingly, the Sc addition which refines the grains and results in fibrous morphology instead of highly faceted Si particles. The addition of precipitation strengthening element Cu can significantly increase the hydrogen content and increase the number of porosity by an order of magnitude. Therefore, in situ observation and X-ray tomography in this study enabled us to understand the key roles of Cu and Sc and control the kinetic process of both eutectic Si and defects for better mechanical performance. [ABSTRACT FROM AUTHOR]

With increasing demands of the high strength and light weight suspension components from automotive industry, aluminum alloys with higher strength than traditional alloys must be developed. In order to meet this requirement for cast Al alloys, higher solute concentration than traditional A356 alloys is needed to enhance the solute and later precipitation strengthening effects. Considering Zn as one of the alloying elements with high solubility in Al, we investigate the effects of Zn addition and related heat treatment parameters on the mechanical properties of Al–Si–Mg alloys by using a combination of experimental and thermodynamic methods. With the addition of Zn, the yield strength (YS) and ultimate tensile strength (UTS) of Al–Si–Mg alloys are significantly improved by up to 52.2% and 8.5% compared with those without Zn additions. After a proper heat treatment, the YS and UTS of Al–Si–Mg–Zn alloys can be further increased by up to 35% and 28%, respectively, compared to the as-cast state. Based on the study, optimal heat treatment parameters for Al–Si–Mg alloys with different Zn contents are proposed. [ABSTRACT FROM AUTHOR]