Effect of Fe, Ni and Cr addition on the wear behavior of hyper-eutectic Al-Si automotive alloy has been studied. Dry sliding wear tests have been conducted using pin-on-disc wear testing machine under normal loads of 20N and constant sliding speed of 0.64 ms-1. Influence of Fe addition to the base alloy increases the wear rate due to the formation of needle beta intermetallics. Ni addition to the alloy does not impede formation of needle-like intermetallic compounds and has no positive effect on the modification of microstructure. Introducing of Cr to the iron-rich alloy changes the beta intermetallics into the modified alpha phases and therefore reduced the detrimental effect of iron. As a result it recovers the strength and wear properties of the experimental alloy. Wear test surfaces were examined by SEM and have shown that Cr added alloy improves wear resistance through mild and smooth abrasive grooves filled with oxides.

The main focus of this study is to examine and evaluate the effect of Fe, Ni and Cr on the corrosion behaviour of hypereutectic Al-Si automotive alloy in 3.5% NaCl solution. Experimental information are attained using conventional gravimetric measurements under different solution temperature and velocity and complemented by resistivity, optical micrograph, scanning electron microscopy (SEM) and X-ray analyzer (EDX) investigations. All the alloys show the negative corrosion rate due to formation of a very thin film of aluminum oxide and hydroxid on the surface. Intermetallic particles in the alloys play a major role in passivity. Temperature accelerates the corrosion and the higher velocity breakdown of the passive film. It also affects the resistivity of the alloys. The results from this study also indicate that the temperature and velocity increase the negative corrosion rate of the alloys due to higher rate of chemical reactions. SEM and EDX analysis indicate that the surfaces compose with a thin layer of aluminum oxide and hydroxide corrosion products.

Al-based automotive alloys with different level of Si content has been conducted on the characterization of machined surfaces in terms of roughness, temperature, chips formation as well as microstructue evaluation under different machining conditions. For this experiment a shaper machine with HSS single point V-shaped cutting tool is used at different cutting speed and depth of cut. The experimental results show that the surface roughness of the alloys decresess with cutting speed and depth of cut but it is more prominent on cutting speed. It is because of  high cutting speed is more associated with the higher cutting temperatur and softening the work material leading to better surface finish. Higher Si added alloys shows the better surface finish due to formation of different intermettalics as more brittle. For brittle and higher hardness it produces the higher temperature during machining. During machining relatively curly and short chips are form by the high Si added alloy becase of its low elongation properties. Fracture surfaces of higher Si added alloy display more crack propagation obtained by the plate-like Si rich intermetallics.

The aim of this study is to investigate the electrochemical corrosion behavior of Al-Si automotive alloys with different levels of Si doping in 0.1 M NaCl solution at room temperature. The study was performed by electrochemical method, using potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The condition of surfaces was characterized by both optical and scanning electron microscopy. Both the EIS and Tafel analyses revealed that the corrosion resistance was improved with the addition of Si up to the eutectic point due to the formation of protective oxide films. The higher Si added alloys showed lower values of current density, while the corrosion potential was shifted to a more positive direction. For higher Si added alloys, a higher amount of Mg2Si was formed as precipitates, which tend to form oxides such as SiO2 and MgO, further protecting the surfaces from corrosion. It can be observed from the micrographs that the scratches from polishing are removed after corrosion. Additionally, the SEM images reveal that corroded surfaces appear to have pits that are less noticeable in alloys with a greater Si content, suggesting thus the formation of a protective layer of oxides.

Effect of Fe, Ni and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy was studied. The test of corrosion behaviour at different environmental pH 1, 3, 5, 7, 9, 11 and 13