The field-induced irreversible transition reported in a previous investigation for a single crystal of TbFe 4 . 4 5 Al 7 . 5 5 (tetragonal ThMn 1 2 structure) at 4.2 K has been studied in more detail. From measurements in high fields, in which a ferrimagnetic moment arrangement is stable, we have determined the value for the intersublattice-coupling constant between the Tb and Fe sublattice moments (J T b F e /k=7.80 K). This value is shown to be in good agreement with the intersublattice-coupling constant obtained by the same method for the isotypic compound GdFe 5 Al 7 that is ferrimagnetic, also in zero field. Using the experimental value of the intersublattice-coupling constant obtained for TbFe 4 . 4 5 Al 7 . 5 5 we have used a simple mean-field model to calculate a value for the compensation temperature expected for the ferrimagnetic modification of this compound (T c o m p =136 K) and found it to be in agreement with experimental observation (T c o m p =135 K).