MICROSTRUCTURES AND MECHANICAL PROPERTIES OF SUBMICROMETER-GRAINED Al ALLOYS PRODUCED BY EQUAL-CHANNEL ANGULAR PRESSING

摘要

Grain refinement was attempted using the equal-channel angular (ECA) pressing technique for a wide range of commercial Al alloys such as 1100, 2024, 3004, 5083, 6061 and 7075. Transmission electron microscopy revealed that grain sizes less than 1 μm are attained in these alloys. Tensile tests at room temperature showed that the strength increases with an increase in the imposed strain during pressing but the elongation to failure remains little changed following a large decrease after the first pressing. Static annealing experiments demonstrated that extensive grain growth occurs above ～200°C in 1100, 3004, 5083 and 6061 but the submicrometer grained structures in 2024 and 7075 are stable even at 300°C.