High Temperature Lubricated Wear of Sand Cast and Die Cast Al Alloys for Continuously Variable Transmission (CVT) and Other Applications
Date of Award
Mechanical, Automotive, and Materials Engineering
Continuously variable transmission, Aluminum alloys, Automotive industry
Light weight alloys like aluminum-silicon (Al-Si) alloys and magnesium alloys are widely utilized in the automobile industry. They have several favorable properties such as high wear resistance and good corrosion resistance at a wide range of temperatures. However, their wear-resistance under harsh operating conditions such as oxidation, creep and thermal fatigue still needs to be improved. In this work, the tribological behaviour of Al-Si alloys die cast A380, die cast ADC10, sand cast A356-T6, die cast B390, and magnesium alloy AE44 were investigated using a block-on-ring tribometer at 93 °C and 130 °C sliding temperatures and fixed sliding speed of 140 mm/s and a load of 200 N.
The wear results of die cast A380 and sand cast A356-T6 were the emphasis of comparison. The results showed that wear rate of sand cast A356-T6 (3.6 × 10−3 mm3/m at 93 °C and 4.7 × 10−3 mm3/m at 130 °C) was six times lower than that of die cast A380 (22 × 10−3 mm3/m at 93 °C and 28 × 10−3 mm3/m at 130 °C).
Based on the microstructural analysis, poor wear behaviour of die cast A380 compared to sand cast A356-T6 samples can be attributed to the presence of AlFeMnSi phases in the die cast A380 alloy microstructure. This was the region where several cracks originated. Sand cast A356-T6 has less Fe content than die cast A380. Fe in sand cast A356-T6 was in the shape of large needle-like β-Al5FeSi phase in its microstructure, which increased the hardness of the material and contributed to the wear resistance. In addition, the worn surface of sand cast A356-T6 produces a continuous oil residue layer, which protects the Al matrix and contributes to the higher wear resistance of sand cast A356-T6. Moreover, a lower wear resistance was observed at higher temperatures for both die cast A380 and sand cast A356-T6 alloys.
Zhang, Xi, "High Temperature Lubricated Wear of Sand Cast and Die Cast Al Alloys for Continuously Variable Transmission (CVT) and Other Applications" (2022). Electronic Theses and Dissertations. 8691.
Available for download on Tuesday, May 30, 2023