The effects of Al upon the deformation mode and tensile properties of Fe-19Mn-5Cr-(0-5.5)Al-0.25C alloys were studied. The deformation mode at room temperature shifted from (ε + α′) martensites, to deformation twinning, to slip, with increasing Al content. The Al increased the stacking-fault energy at a rate of 10mJ/mm2wt%. This was sufficiently high to give rise to large variations in the deformation mode. Body-centred tetragonal α′ martensites were introduced during deformation at low temperatures, together with deformation twins. The formation of the α′ martensites was preceded by the formation of deformation twins. A Fe-19Mn-5Cr-3.5Al-0.25C composition exhibited elongations or more than 65% at both room temperature and 77K.

Effect of Aluminium on Deformation Mode and Mechanical Properties of Austenitic FeMnCrAlC Alloys. B.W.Oh, S.J.Cho, Y.G.Kim, Y.P.Kim, W.S.Kim, S.H.Hong: Materials Science and Engineering A, 1995, 197[2], 147-56