Study on the Effects of Squeeze Pressure on Mechanical Properties and Wear Characteristics of Near Eutectic Al–Si–Cu–Mg–Ni Piston Alloy with Variable Mg Content

Abstract

In the present work, the effects of pressure on the wear resistance characteristics, mechanical properties and the microstructures of Al-Si piston alloys that have variable Magnesium (Mg) content are studied. The paper begins with an explanation of the desirable properties of eutectic Al-Si alloys and why these chemical and mechanical properties are desirable in the fabrication of light weight machine components. The methods for further strengthening the alloys using alloying elements such as Ni, Cu and Mg, and applying heat treatment are also discussed. The paper also emphasises on the addition of Magnesium, and compares the traditional gravity die casting with a novel hybrid technology known as squeeze casting. In the results and discussion section, the microstructure properties of the Al-Si both as-cast and after heat treatment conditions are discussed. The mechanical and wear properties as well as the implications of pressure on the alloys are also discussed in details. SEM analyses of wear surface and fracture behavior on the as cast Al-Si alloys and after heat treatment, reveal that squeeze pressure increases fracture ductility as well as resistance to wear; more so upon heat treatment. It is also determined that the hardness and UTS values increases with increase in Magnesium content and reaches the maximum values when Mg content is at 1 % of the alloy's composition.

Effect of Ni and Sr on the microstructure and tensile properties of the squeeze cast Al‐Si‐Cu alloy at elevated temperatures

“…In the past decades, great research efforts have been made to develop Ni-containing AlÀ Si alloys for engine applications. From previous studies, the transition alloying element nickel (Ni) is found to be an effective element for improvement of mechanical properties of AlÀ Si alloy at elevated temperature especially on hardness and strength [4][5][6][7][8][9]. Studies on the modification with nickel on the morphologies on aluminum alloys conclude that the presence of additional transition alloying elements in the aluminum alloy system allows many complex intermetallic phases to form including Al 2 Cu, Al 3 Ni, Al 7 Cu 4 Ni, Al 9 FeNi and Al 5 Cu 2 Mg 8 Si 6 .…”

“…To minimize the side effect of Sr addition, proper selection of casting processes becomes essential and critical, in which the advantages of alloying elements in AlÀ Si alloys could be maximized. Squeeze casting, also known as liquid metal forging, extrusion casting and pressure crystallization, has become an emerging technology for manufacturing light weight components alloy with aluminum and magnesium alloys [27][28][29][30][31][32][33][34][35][36][37][38]. This is because the process involves the solidification of a molten metal in a closed die under an imposed high pressure which keeps entrapped gases in solution and squeeze molten metal from hot spots to incipient shrinkage pores.…”

Experiment on Hardness and Impact Strength of Recycled Aluminum Alloys by Metal Casting Process

“…The effects of pressure on the wear resistance characteristics, mechanical properties and the microstructures of Al-Si piston alloys that have variable Magnesium (Mg) content are studied [12]. The methods for further strengthening the alloys using alloying elements such as Ni, Cu and Mg, and applying heat treatment are also discussed.…”

“…The maximum of hardness index shows 62.83 BHN at 810 o C of pouring temperature on on Al-2.81Zn-2.6Si alloy [10]. The impact toughness of Al-Si-Mg was investigated [12], it is reported that impact index is about 25 joule. The effects of two-pass friction stir processing (FSP) on the impact toughness of as-cast Al-12Si alloy was studied [17].…”

“…This increment rate is almost the same with that of the εf (7.4 times). Pratheesh et al [12] is reported that hardness on near eutectic Al-Si-Cu-Mg-Ni piston alloys about 63 BHN. Differences hardness and impact strength are usually caused by phase morphological variations as shown by SEM micrographs (Fig.…”