Frictional Properties of Cast Al-Si-Cu-Zn Alloy in DOT4 Fluid

Abstract

Frictional properties of cast aluminium based silicon-copper-zinc (Al-Si-Cu-Zn) alloy were studied in and without DOT4 brake fluid environment using a standard ball on disk tribometer. Substrates were prepared by grinding and polishing to 0.2 m mirror-like, smooth and uniform surface. The examinations of the polished and worn surface morphologies and microstructural analysis were carried out using high resolution metallurgical microscope. Standard size 6 mm diameter alumina ball was rubbed on the cast Al-Si-Cu-Zn alloy specimens surface using different loads (1~10 N) at room temperature (25.00 °C) and atmospheric humidity of 50%. Increased normal force Fn loading initially gave a considerable decline in coefficient of friction (CoF) values for the dry and wet sliding conditions but latter, the CoF stabilized over wide time range for both contact situations. The CoF values reduced from average of  = 0.415 to 0.174 at 1N;  = 0.4997 to 0.1689 at 5 N; and  = 0.82 to 0.193 at 10 N respectively during the dry and wet sliding contacts. The results showed that the alloy was resistant to wear under the two experimental conditions.