Abstract: This study discusses the effect of elevated temperature on the hardness of fatigue test specimens which are made of aluminium alloy, AA6061-T6. The fatigue strength of material normally decreases with temperature increase. The fatigue tests were performed on aluminium alloy specimen using servo-hydraulic fatigue testing machine in concordance to an ASTM E466 standard. Three types of loadings, i.e., Constant-Aplitude Loading (CAL), high-to-low and low-to-high sequences has been used for the tests at various temperature levels of 27, 70, 150 and 250°C. The load sequence has been derived from an original fatigue loading of an engine mount bracket of 1300 cc automobile. Fatigue fracture surfaces were then sectioned and the hardness of specimen below the fracture surface was inspected using Rockwell hardness tester machine. Results indicate that the fatigue lives were significantly influenced by the load sequences and temperature levels. The hardness of material under fracture surface also found influenced by the elevated temperature. Finally, the hardness of the fracture surface will be relates to the fatigue lives at elevated temperature.
K.A. Zakaria, S. Abdulllah, M.J. Ghazali and M.B. Ali, 2016. Influence of Elevated Temperature on the Fatigue Fracture Surface Hardness of Aa6061. Journal of Engineering and Applied Sciences, 11: 2130-2135.