Effect of Squeeze Casting Parameters on the Wear Properties of A390 Aluminum Alloy
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Copyright Ó 2020 American Foundry Society https://doi.org/10.1007/s40962-020-00507-1
Abstract In this paper, the effects of squeeze casting parameters on the wear behavior of A390 aluminum alloy were investigated. For this purpose, the experiment was designed according to L9 Taguchi array that the squeeze pressure (60, 90 and 120 MPa), the superheats of liquid metal (50, 100 and 150 °C) and the die preheating temperature (200, 250 and 300 °C) were selected as the independent variables at three levels. On the contrary, the microstructure characteristics, the weight loss of specimen after wear test and friction coefficient were examined as dependent variables. The microstructural characterizations were also performed using optical microscopy equipped with image analyzer and SEM equipped with EDS. The squeeze casting
was performed with a 20-ton hydraulic press in a cylindrical shape. According to the results, the increase in squeezing pressure from 60 to 120 MPa within the tested range leads to a decrease in primary silicon area by 48% and a decrease in silicon eutectic by 44.4%; however, applied pressure did not have any significant effects on morphology of phases. The wear tests were carried out using a computer-controlled pin on disk wear test machine in ambient temperature.
Introduction
formation of coarse and brittle primary silicon particles, which reduces the tensile strength and wear resistance.7 Alloy microstructure in traditional casting method include primary silicon, an alpha dendritic phase, a blade-like silicon eutectic phase and intermetallic phases of some elements such as copper, magnesium, manganese, and iron.8 In order to decrease the porosity in the material, the pressure casting namely die and squeeze casting methods is applied.9 The wide range solidification of this alloy can lead to a large volume of porosities. The size and morphology of porosities have a great influence on the freezing rate and the amount of gas contained within the molten metal. By decreasing the cooling rate and increasing the dendrite arm spacing, these porosities are trapped between these arms and their amount rises sharply.10 There are two basic squeeze casting methods depending on whether the pressure is applied directly onto the solidifying cast product via an upper or male die (punch) or the applied pressure is exerted through an intermediate feeding system: the direct and indirect squeeze casting mode.10 Applied pressure on the molten metal by a hydraulic press during solidification causes the molten metal to feed areas susceptible to shrinkage and also dissolves trapped gas into the
Aluminum–Silicon Alloys possess lightweight, high specific strength, and better heat transfer ability, which makes them suitable material to replace components made of ferrous alloys. They are utilized in different types of Internal Combustion engines.1 Hypereutectic Al–Si alloys are considered ideal choice for applications which require distinctive properties such as high level of wear resistance, good mechanical properties, low the
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