한국주조공학회

The purposes of this study were to investigate the microstructural changes in alloy ribbons of Al-Fe-Mo-Si quarternary system at 450~500℃, and to study the coarsening mechanism of fine precipitates. Using the hot stage in TEM, in situ microstructural changes in Al-4Fe-0.5Mo-1.5Si alloy ribbon and Al-8Fe-2Mo-1.5Si alloy ribbon have been examined successively up to 60 hours at 450℃ and 500℃. Cell structure in zone B of Al-4Fe-0.5Mo-1.5Si alloy ribbon was observed to collapse even in 10 minutes by in-situ heating at 450℃ and the size of precipitates in zone B increased twice in 60 hours. The precipitates in zone A of Al-4Fe-0.5Mo-1.5Si alloy ribbon showed slower coarsening rate than those in zone B by in-situ heating at 450℃. The precipitates in zone A of Al-8Fe- 2Mo-1.5Si alloy ribbon increased 50% by in-situ heating at 500℃ in 50 hours compared to the initial precipitates while any microstructual change in zone B was not observed by in-situ heating at 500℃ up to 50 hours. Only the precipitates in zone A of Al- 4Fe-0.5Mo-1.5Si alloy ribbon satisfied r^3∝t relationship of coarsening mechanism.