2017 | AFC ACCOMPLISHMENTS 87 Figure 3. As-drawn ATF FeCrAl alloy tubes and microstructure characterization results. process.The area reduction ratio and the extrusion temperature are key to controlling the quality of the master bars and the grain structure (Figure 3). Because of the limited deformation ability of FeCrAl alloys, especially at ambient temperatures, a controlled, uniform grain structure with relatively small grains (