Temperature effect on fracture behaviour of an alumina particulate-reinforced 6061-aluminium composite

The effect of temperature on the fracture behaviour of a peak-aged alumina particulate 6061 aluminium composite was studied in the range of 25 to 180° C. The fracture toughness was found to be independent of test temperature. The role of the reinforcement phase was examined in detail at 180° C, and compared to observations at room temperature, by using an interrupted test methodology. Ductile fracture occurred at all temperatures. At room temperature the fractured particles acted as void nucleation sites and at 180° C both debonded and fractured particles were responsible for void nucleation. Large particles were found to be susceptible to fracture and nucleate microvoids earlier than small particles. A decrease in the range and size of the reinforcement phase would increase the fracture resistance for this MMC material.On leave at the Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.