  We present the magnetic phase diagram of TbMn1-xFexO3 substitutional solid
solution in the whole concentration range 0 <= x <= 1 as determined from
magnetization and specific heat measurements. We have found that the dominant
magnetic ion in the concentration range 0 <= x < 0.3 is manganese, while iron
ions do not create independent magnetic structure, but strongly affect magnetic
properties of the parent compound by reducing transition to magnetically
ordered state and transition into a cycloidal phase. The magnetism in the
concentration range 0.3 < x <= 1 is driven by the Fe sublattice. The manganese
ions again do not order in long range magnetic ordered state, but stabilize
four different magnetic structures of Fe sublattice above 2 K. The magnetic
ordering of Tb sublattice was observed only on parent compounds TbMnO3 and
TbFeO3 and for doping level below 0.1, or over 0.9.
