Phase transformations in Fe72−xAl28Tix (x=0,2,6,9) alloys induced by severe plastic deformation

Abstract Mechanical deformation is induced in Fe 72− x Al 28 Ti x alloys ( x =0,2,6,9) by filing cast and homogenized ingots to fine powder. The phase transformations induced due to the deformation and subsequent annealing are followed by Mossbauer spectroscopy, XRD, and magnetization measurement. As a result of filing, the long range order is destroyed and pockets of B2, DO 3 and α -phase are created. While the α -phase (random solid solution of Al in Fe) dominated in the strained Fe 72 Al 28 alloy ( x =0), all the three phases were formed in significant amount in the Fe 63 Al 28 Ti 9 alloy ( x =9). Heating at around 400°C for 10 h completely recovered the ordered structure in Fe 63 Al 28 Ti 9 alloys but similar treatment on the strained Fe 72 Al 28 alloys favoured transformation from random distribution to a mixed phase of DO 3 , α and B2. Heating of the strained Fe 72 Al 28 samples to 900°C for long time followed by slow cooling induced strong DO 3 order. Similar treatment on the strained Fe 63 Al 28 Ti 9 alloys take them dominantly to nonmagnetic ordered phase. The behaviour of other alloys ( x =2,6) are intermediate between these.