Mechanical Performance of Zr‐Containing 354‐Type Al‐Si‐Cu‐Mg Cast Alloy: Role of Additions and Heat Treatment

Abstract

In this article, the volume fraction of intermetallic compounds in Zr-containing 354-type Al-Si-Cu-Mg alloys, characteristics of eutectic Si particles, and tensile, hardness, and impact properties have been evaluated with varying Ni and Mn contents and combination. The results revealed that additions of Ni and Mn in different amounts and combinations increased the volume fraction of intermetallic compounds in the tailored alloys, compared to the base alloy (cf. 12.21% for 4% Ni-containing alloy with 2.5% for base alloy), producing a significant effect on the mechanical performance. The proposed additions enhanced the mechanical performance of the alloys, namely, the ambient- and elevated-temperature tensile properties, hardness values, and impact properties. For the Mn-containing alloys, the improvement in properties was attributed to the formation of sludge particles in the form of blocky α-Al15(Fe,Mn)3Si2 alongside the script-like α-iron phase that resisted crack propagation. The precipitation of Ni-bearing phases such as Al9FeNi, Al3CuNi, and Al3Ni in the Ni-containing alloys improved the mechanical properties through hindering cracks propagation. Interestingly, addition of 0.75 wt.% Mn to the base alloy proved to be competitive in strength values to the addition of 2 and 4 wt.% Ni, and better in terms of ductility values. The investigations showed that the variations in hardness and impact values follow the same trend as variations in the percentage volume fraction of intermetallic compounds, i.e., maximum property value is associated to the alloy with highest volume fraction of intermetallic compounds. Furthermore, the impact properties showed higher dependency on Al2Cu phase particles rather than the eutectic Si particles.

High‐Temperature Tensile Fractography of Zr‐, Ni‐, and Mn‐Containing Al‐Si‐Cu‐Mg Cast Alloys

“…e base alloy in this research work is 354-type alloy with a minor addition of Zirconium (Zr) (∼0.3 wt.%). is alloy was selected based on its improved room-and high-temperature tensile properties as reported in previous studies in the same research group [14,19]. e as-received 354 alloy ingots were cut, dried, and melted in a 70-Kg capacity SiC crucible using an electric resistance furnace.…”

“…Many studies [14][15][16][17][18][19][20][21][22] have been carried out in the past decade on how to maintain the mechanical properties of aluminum alloys at service temperatures that exceed 200°C. Among these, the addition of small amounts of transition metals was found to be a promising approach to maintain the mechanical properties of aluminum alloys at temperatures of up to 300°C.…”

“…Abdelaziz et al [14,19] studied the mechanical behavior of similar system of alloys and concluded that the addition of Zr, Ni, and Mn enhances the overall mechanical properties of 345 cast alloy including tensile properties at both ambient and 250°C, hardness values, and impact properties. In particular, Abdelaziz et al [14] stated that the enhancement in mechanical properties of Mn-containing alloys were attributed to the formation of blocky α-Al 15 (Fe, Mn) 3 Si 2 and the script-like-α-iron phase. Also, it was stated that [19] the prolonged thermal exposure of alloys containing Zr, Ni, and Mn at 250°C has a detrimental effect on the mechanical properties of the studied alloys owing to the coarsening of the strengthening precipitates.…”

High-temperature mechanical properties of cast Al–Si–Cu–Mg alloy by combined additions of cerium and zirconium

“…In recent years, efforts have been made for improving cast alloys mechanical properties, mainly in superior temperatures than the ones of the conventional applications. A significant number of studies on cast Al-Si-Cu-Mg alloys [13][14][15][16][17][18] were conducted due to its important applications in the transport sector in a large variety of components. Basically, in order to improve the strength, particularly at high temperatures, alloying elements that exhibit both limited solid solubility and low diffusivity in Al must be added [19].…”

“…Basically, in order to improve the strength, particularly at high temperatures, alloying elements that exhibit both limited solid solubility and low diffusivity in Al must be added [19]. Recent studies on aluminum alloys modified with the minor Zr additions [3,5,16,[20][21][22]] demonstrated a significant enhancement in high-temperature mechanical properties due to the increase of volume fraction of highstable intermetallic phases formed in the microstructure.…”