Grain growth behaviour and consolidation of ball milled nanocrystalline iron-chromium alloys

Nanocrystalline iron-chromium alloys may provide considerable corrosion resistance, even at low chromium contents. However, processing of such alloys could be a challenge. This paper describes successful synthesis of nanocrystalline Fe-Cr alloys by ball-milling route. In the absence of suitable hot compaction facility, the alloy powder could be successfully compacted close to the desired density, by employing a step of prior annealing of the powder followed by compaction at a relatively low temperature. Grain growth behaviour of Fe-Cr nanocrystalline alloys was investigated at 500, 600 and 700 degrees C. At 500 degrees C, no appreciable grain growth was observed, after the initial period. However, a sudden and rapid grain growth was observed after 90 minutes at 600 degrees C, and after 30 minutes at 700 degrees C. The paper also describes the success in the processing of the nanocrystalline iron-chromium alloys.