Comparative Study on Microstructure and Corrosion Resistance of Al-Si Alloy Cast from Sand Mold and Binder Jetting Mold

Abstract

This investigation is focused on the corrosion evaluation of an as-cast Al-Si alloy, obtained by two different casting methods: traditional sand casting and three-printing casting, using a binder jetted mold. The experimental results are discussed in terms of chemical composition, microstructure, hardness, and corrosion behavior of two different casting parts. The microstructure and composition of the sample before and after the corrosion tests was analyzed using light microscopy (OM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (DRX). The corrosion of the two processed castings was analyzed using anodic polarization (PA) test and electrochemical impedance spectroscopy (EIS) in an aerated solution of 3.5% by weight NaCl, similar to the seawater environment. After the corrosion process, the samples were analyzed by inductively coupled plasma/optical emission spectrometry (ICP/OES); the composition was used to determine the chloride solution after immersion times. The sample processed by binder jetting mold showed higher corrosion resistance with nobler potentials, lower corrosion densities, higher polarization resistance, and more stable passive layers than the sample processed by sand casting. This improvement of corrosion resistance could be related to the presence of coarse silicon particles, which decrease of cathodic/anodic ratio and the number of micro-galvanic couples, and the lower amount of intermetallic β Al-Fe-Si phase observed in cast alloy solidified in binder jetting mold.

The Influence of Alloying Elements on the Microstructure and Properties of Al-Si-Based Casting Alloys: A Review

“…Regarding corrosion, Si is present as a secondary phase embedded in the matrix [1]. The electrochemical behavior of dispersed particles differs from that of the matrix, meaning they might act as anodes or cathodes with respect to the matrix, leading to the formation of galvanic pairs [16,17]. Si is cathodic and is present in relatively high amounts in cast Al alloys [1].…”

Additive Manufacturing Research and Applications

“…This Special Issue offers a wide scope in the research field around 3D printing, including the following [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]: the use of 3D printing in system design, AM with binding jetting, powder manufacturing technologies in 3D printing, fatigue performance of additively manufactured metals such as the Ti-6Al-4V alloy, 3D-printing method with metallic powder and a laser-based 3D printer, 3D-printed custom-made implants, laser-directed energy deposition (LDED) process of TiC-TMC coatings, Wire Arc Additive Manufacturing, cranial implant fabrication without supports in electron beam melting (EBM) additive manufacturing, the influence of material properties and characteristics in laser powder bed fusion, Design For Additive Manufacturing (DFAM), porosity evaluation of additively manufactured parts, fabrication of coatings by laser additive manufacturing, laser powder bed fusion additive manufacturing, plasma metal deposition (PMD), as-metal-arc (GMA) additive manufacturing process, and spreading process maps for powder-bed additive manufacturing derived from physics model-based machine learning.…”

Quality of automotive sand casting with different wall thickness from progressive secondary alloy

“…This phase is characterized by a very high tendency to corrosion, is very brittle but hard. Moreover, the plate-like β-Al5FeSi cause an expansion in pore sizes, even though the platelets also limit pore growth (Bacaicoa, 2019;Castro-Sastre, 2021;Ji, 2013;Kasala, 2011;Kuchariková, 2018;Mahta, 2008).…”