Improvement of room temperature tensile properties for Fe3Al-based alloys by thermomechanical and annealing processes

The effects of thermomechanical and annealing processes on room temperature tensile properties of Fe3Al-based alloys have been investigated. It is fou nd that the thermomechanical process affects the room temperature tensile p roperties of Fe3Al-based alloys greatly. It is very important to control th e hot deformation process so that a fine grain microstructure can be obtain ed before the final warm-rolling process. A higher room temperature ductili ty combined with a higher yield stress can be obtained by refining grains o f Fe3Al-based alloys and obtaining the B2 ordered structure with a suitable surface state, such as oil film, Al2O3 film and an aluminium-poor region n ear the surface. The intrinsic factors, such as microstructure and crystal structure, and extrinsic factors, such as surface condition, must be consid ered when the sensitivity to environmental embrittlement is investigated. A n advanced thermomechanical process, named controlled thermomechanical proc ess, to further improve room temperature tensile properties has been develo ped. It consists of hot forging an ingot to 20 mm at 1000-1200 degrees C, h ot rolling it to 10 mm at 850-1000 degrees C, warm rolling to 5 mm thicknes s at 500-680 degrees C, then annealing at 800 degrees C for 1 h, then warm rolling to 2 mm thickness at 500-680 degrees C. (C) 1999 Elsevier Science S .A. All rights reserved.