Enhancement of the Mechanical Properties in Al–Si–Cu–Fe–Mg Alloys with Various Processing Parameters

Abstract

In this research, various processing conditions were implemented to enhance the mechanical properties of Al-Si alloys. The silicon content was varied from hypoeutectic (Si-10 wt.%) to eutectic (Si-12.6 wt.%) and hypereutectic (Si-14 wt.%) for the preparation of Al-XSi-3Cu-0.5Fe-0.6 Mg (X = 10–14%) alloys using die casting. Subsequently, these alloys were hot-extruded with an optimum extrusion ratio (17:1) at 400 °C to match the output extruded bar to the compressor size. An analysis of the microstructural features along with a chemical compositional analysis were carried out using scanning electron microscope along with energy dispersive X-ray spectroscopy and transmission electron microscope. The SEM micrographs of the extruded samples displayed cracks in primary Si, and the intermetallic (β-Al5FeSi) phase was fragmented accordingly. In addition, the silicon phase was homogenously distributed, and the size remained constant. The mechanical properties of the extruded samples were enhanced by the increase of silicon content, and consequently the ductility decreased. By implementing proper T6 heat treatment parameters, coherent Al2Cu phases were formed in the Al matrix, and the Si phase was gradually increased along with the silicon content. Therefore, high tensile strength was achieved, reaching values for the Al-XSi-3Cu-0.5Fe-0.6Mg (X = 10–14%) alloys of 366 MPa, 388 MPa, and 420 MPa, respectively.

Specific Response of Additively Manufactured AlSi9Cu3Fe Alloy to Precipitation Strengthening

“…Two precipitate shapes are present; needle-like precipitates of Si, with a length of 55 ± 13 nm and thickness of 6 ± 1 nm, and rather spherical precipitates of 16 ± 3 nm in diameter which are thus likely Al 2 Cu-based precipitates. The increased precipitate density can be related to the solution treatment during the T6 regime in which the Si intercellular network dissolved; an increased Si content in Al matrix promotes the diffusion coefficient of Cu in aluminium [17].…”

Promoted Anodizing Reaction and Enhanced Coating Performance of Al–11Si Alloy: The Role of an Equal-Channel-Angular-Pressed Substrate

“…In this work, we will use an Al–Si alloy for study. The Al–Si series is the most important system of the Al alloys, because of its excellent castability, weldability, and superior wear resistance [29,30,31,32,33,34,35]. The content, size, scale, and distribution of the Si phase have been commonly believed to strongly affect the mechanical properties and castability of the alloys [36,37,38,39,40,41,42,43].…”

Effects of the Aluminum Alloy with Intermetallic a Phase on the Microstructural and Corrosion Resistance

“…Several authors have studied the Vickers microhardness, including Tillová, et al [5], who, studying the intermetallic phases in Al-Si recycled alloys presents a microhardness of 483 HV, in addition, Isadarea, et al [17] studied Mechanical Properties of 7075 Aluminum Alloy, they found for this alloy the microhardness of 201 HV, however, the microhardness of 567 HV for Al-Si-Cu-Mg-Fe extruded alloy was measured by the authors Ahn [18]. Though, some authors, Kubota [19] and Xu, et al [20] determined the microhardness of pure aluminum, around 50 HV.…”