Technological plasticity studies of the FeAl intermetallic phase-based alloy

Results of hot torsion tests of the Fe–40Al–5Cr–0.2Mo–0.2Zr–0.02B alloy are presented in the paper. The alloy was obtained by melting in an induction furnace. The tests were carried out using a plastometer of the Sataram type in the temperature range of 1123–1273 K and strain rates of 0.06, 0.24, 0.48 and 2.42 s−1 that were close to those used in plastic working processes. In the alloy studied the super-plasticity phenomenon was observed. The shape of the flow curves indicated that dynamic recrystallisation occurred during the super-plastic deformation. This was confirmed by studies of the alloy structure. Also traces of dynamic recovery were observed. The value of the activation energy Q=343 kJ/mol for dynamical recrystallisation is close to the activation energy of aluminium diffusion in the FeAl phase. The results have revealed that cast FeAl-based alloy can be process by superplasic forming in the range 1123–1223 K at strain rates about 1 s−1.