한국주조공학회

Some alloying elements such as Cr, B, Ti and Si were added individually or as a mixture to Fe-30 at.%Al alloys. The alloys were melted using an arc furnace and then heat-treated for homogenization at 1000°C for 7 days and followed by rolling at 1000"C. The alloying elements on rolling characteristics were investigated by the microstructures and fracture mode before and after rolling. The microstructures before rolling showed that all of the alloys had equiaxed grains. On the other hand, the microstructures of rolling plane as well as its perpendicular plane became elongated after rolling. The alloys such as Fe-3oAl, Fe- 3oAl-3Ti, Fe-3oAl-0.5B, Fe-3oAl-5Cr and Fe-3oAl-3Ti-0.5B revealed better rolling behaviour from the point that intergranular and cleavage fractures were not fundamentally occurred. But the addition of 5Ti or 3Si to Fe-Al alloys had detrimental effects. The Ti-added alloy system such as Fe-3oAl-5Ti, Fe-3oAl-5Ti-5Cr, Fe-3oAl-3Ti-5Cr and Fe-3oAl-5Ti-0.5B were cracked through grain and showed cleavage fracture. The Si-added alloy system such as Fe-3oAl-5Si, Fe-27Al-3Si and Fe-27Al-5Cr-3Si were cracked along the grain boundary and showed intergranular fracture. Do3 <-> B2 transition temperature of Fe-3oat.%Al alloy was 520°C, whereas the addition of 3Ti and 3Ti+0.5B comparably increased the temperature to 797 and 773°C, respectively.

Rolling, Fracture mode, Equiaxed grains, Transition temperature, Intergranular fracture, Cleavage fracture