High temperature deformation behaviour of high carbon cast AIM and ESR Fe3Al alloys

The Fe(3)AI alloys with the following compositions, Fe 16.2Al-0.54C and Fe- 15.5Al-1.1C were melted under flux cover by air induction melting (ATM). Co nventional casting defects like shrinkage pipes and microporosity were obse rved in AIM ingots. Electroslag remelting (ESR) of AIM ingots has resulted in clean. sound ingots free from casting defects. Isothermal, constant stra in rate compressive tests were carried out on a DARTEC computer controlled servo hydraulic testing machine over a range of strain rates. 10(-1) to 10( -1) s(1), and temperatures of 1073-1273 K. The cast ESR high carbon Fe-15.5 Al-1.1C alloy exhibited high how stress as compared to the low carbon Fe-16 .2Al-0.54C alloy. This may be attributed to the presence of a high volume f raction of hard Fe3AlC0.5 particles in the high carbon alloy. The flow stre ss levels of ESR cast Fe-15.8Al-1.1C alloys were the same in both longitudi nal and transverse directions and lower than those of the cast AIM alloy. T his may be due to a fine homogeneous axially oriented columnar grain struct ure free from defects observed in cast ESR ingot. It would appear from the limited present work that isothermal forging of both AIM and ESR ingots of the high carbon Fe3Al alloy is possible even at temperatures of 1073 K. Non -isothermal rolling or press forging at a moderate strain rate of 10(1)s(-1 ) would be at starting temperature of 1273 K. (C) 2001 Elsevier Science B.V . All rights reserved.